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An inex of liquid terms

acre foot (ac ft or af)
a unit of volume used to measure the capacity of reservoirs. One acre foot is a volume one foot deep covering an area of one acre. Thus an acre foot contains 43 560 cubic feet or about 1233.482 cubic meters (0.123 348 hectare meter). The symbol af is widely used in reservoir management in the U.S., often in combinations such as kaf (1000 acre feet) or maf (million acre feet; this symbol should be Maf).

ale gallon
a traditional unit of liquid volume in Britain and the U.S., the ale gallon was equal to 282 cubic inches (4.6212 liters) or about 1.2208 U.S.liquid gallon (1.0165 British imperial gallon). Standardized in the sixteenth century under Queen Elizabeth I, the ale gallon remained in use well into the nineteenth century but is obsolete today. It is also called the beer and ale gallon.

amber
an old English unit of volume, used for both liquids and dry goods. The amber was equal to about 4 bushels or roughly 140 liters

amphora
a historic unit of volume. An amphora is the volume of an urn or jar of the same name. These urns were tall, with handles near the top on both sides (the word amphora comes from two Greek words meaning "on both sides" and "carry"). Amphoras were the containers of choice for shipping wine and many other commodities in the ancient world. Archaeologists report that the Greek amphora held about 38.8 liters (10.25 U.S. liquid gallons, or 8.54 British imperial gallons). The Roman amphora was smaller, about 25.5 liters (6.74 U.S. gallons or 5.61 British imperial gallons).

anker or anchor
a small wine barrel used in Britain and elsewhere in northern Europe. In England an anker usually held 10 wine (U.S. liquid) gallons (37.85 liters); the Scottish anker held 20 Scots pints (about 34 liters). The word anker is of Dutch origin.

apothecary weights
a version of the troy weight system formerly used by apothecaries (pharmacists). The troy pound, equal to 373.242 grams or 13.165 72 avoirdupois ounces, is always divided into 12 ounces, each ounce being equal to 480 grains. In the apothecary system, the ounce is divided into 8 drams (60 grains) each containing 3 scruples (20 grains). There is a parallel system of liquid volume measure in which the fluid ounce is divided into 8 fluid drams (or fluidrams) each containing 3 fluid scruples. The apothecary system continued in use into the early twentieth century, but it has been replaced everywhere in pharmacy by the use of metric units.

artaba
a historic unit of volume, used for both liquid and dry measurement throughout the Middle East. In ancient times the artaba varied in size between about 35 and 55 liters. In recent centuries the Arab artaba, equal to about 66 liters, was a common unit in both Arab and non-Arab parts of the area.

aume
an old English wine measure equal to about 40 gallons (roughly 150 liters). The aume is the English version of a German unit, the ohm [2].

ball
a unit measuring the degree of ice coverage of polar seas. One ball equals 10% coverage. The unit was invented by the Russian naval officer N. N. Zhubov (1895-1960).

balthazar
a large wine bottle holding about 12 liters, 16 times the volume of a regular bottle.

bar (b)
a metric unit of atmospheric pressure, equal to one million dynes per square centimeter, 100 kilopascals, 750.062 torr, 1.019 72 kilograms of force per square centimeter (kgf/cm2), or about 14.503 78 pounds per square inch (lbf/in2). The word comes from the Greek baros, "weighty." We see the same root in our word, barometer, for an instrument measuring atmospheric pressure. One bar is just a bit less than the average pressure of the Earth's atmosphere, which is 1.013 25 bar. In practice, meteorologists generally record atmospheric pressure in millibars (mb). In English-speaking countries, barometric pressure is also expressed as the height, in inches, of a column of mercury supported by the pressure of the atmosphere. In this unit, one bar equals 29.53 inches of mercury (in Hg).

barge
an informal unit of volume used in the U.S. energy industry. The barges used on American rivers customarily carry about 25 000 barrels of oil (see barrel [2] below). This is equivalent to 1.05 million gallons, roughly 1400 register tons, or about 3975 cubic meters.

barrel (bbl or brl or bl)
a commercial unit of volume used to measure liquids such as beer and wine. The official U. S. definition of the barrel is 31.5 gallons, which is about 4.211 cubic feet or 119.24 liters. This unit is the same as the traditional British wine barrel. In Britain the barrel is now defined to be 36 imperial gallons, which is substantially larger: about 5.780 cubic feet or 163.66 liters. This unit is slightly smaller than the traditional British beer and ale barrel, which held 5.875 cubic feet or 166.36 liters. There are other official barrels, defined in certain U.S. states; most of them fall in the general range of 30-40 gallons. A barrel of beer in the U.S., for example, is usually 31 U.S. gallons (117.35 liters). The origin of the standard symbol bbl is not clear. The "b" may have been doubled originally to indicate the plural (1 bl, 2 bbl), or possibly it was doubled to eliminate any confusion with bl as a symbol for the bale (see above

barrique
a large French wine barrel holding 225 liters (about 59.44 U.S. gallons).

bottle (btl)
a unit of volume. Like actual bottles, this unit varies according to the nature of the contents. For a long time in the U.S., a bottle of milk was 1 quart (946.36 milliliters), a bottle of whiskey was 1 fifth (757.1 milliliters), and a bottle of champagne was 2/3 quart (630.91 milliliters). In the British Empire, a common bottle size was 2/3 Imperial quart (757.68 milliliters), a unit known as the "reputed quart." Today wine is customarily sold in bottles containing 750 milliliters (about 25.3605 U.S. fluid ounces or 26.3963 British Imperial fluid ounces). See also quart [2]. Other countries have traditional units of about this size. For example, the Russian boutylka contains 768.95 milliliters.

breakfast cup
a unit of liquid volume, used in food recipes in Britain. The breakfast cup corresponds to the cup used by American cooks, except that it is based on British Imperial units. Thus it equals 1/2 Imperial pint. This is equivalent to 10 Imperial fluid ounces, 17.339 cubic inches, 1.20 U.S. cup, or about 284 milliliters. This unit is also called a tumblerful.

British thermal unit (Btu or BTU)
a unit of heat energy defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. In America the British thermal unit is sometimes called the heat unit. In defining the Btu, it is necessary to specify the temperature of the water; thus there have been several definitions over the years. However, one Btu is equal to about 251.996 (small) calories, or 0.251 996 of the (kilo-)calories counted by dieters. Using the current definition of the calorie (the IT calorie), one Btu equals approximately 778.169 foot pounds, 1.055 056 kilojoules or 0.293 071 watt hour. The symbol BThU has also been used, especially in Britain.

butcher
a unit of volume for beer in South Australia. A butcher of beer is a glass holding 200 milliliters (about 7 imperial fluid ounces). This is called a glass [3] or a seven in other parts of Australia.

butt
a traditional unit of volume used for wines and other alcoholic beverages. A butt is generally defined to be two hogsheads, but the size of hogsheads varies according to the contents. In the United States a hogshead is typically 63 gallons and a butt is 126 gallons: about 16.844 cubic feet or 476.96 liters. In Britain, a butt of beer is 108 imperial gallons: about 17.339 cubic feet or 490.98 liters. The word comes from the Roman buttis, a large cask for wine.

centiliter (cl or cL)
a common metric unit of volume. One centiliter equals 10 cubic centimeters; this is about 0.610 24 cubic inch, 0.3318 U.S.fluid ounce or 0.3519 British fluid ounce. In the kitchen, a centiliter is roughly equal to 2 U.S. teaspoons (or 0.704 British tablespoonful).

centimeter of water (cmH2O, cm WC, cm CE, cm WS)
a unit of pressure equal to the pressure exerted at the Earth's surface by a water column (WC) 1 centimeter high. This is about 98.067 pascals, 0.980 67 millibars, 0.3937 inch of water, or 2.04 pounds per square foot. The unit is used in respiratory medicine and elsewhere to measure air pressures. The French symbol is cm CE (colonne d'eau), and the German symbol is cm WS (Wassersäule).

charka
a traditional Russian unit of volume containing about 123.0 milliliters, 4.159 U.S. fluid ounces or 4.329 imperial fluid ounces. There are 6.25 charki in a boutylka (bottle) and 10 in a schtoff. The word charka means a cup or glass.

coffeespoon
a unit of volume formerly used in U.S. food recipes. A coffeespoon is 1/2 teaspoon, 1/12 fluid ounce, or about 2.5 milliliters

congius
a historic unit of liquid volume. The Roman congius was equal to about 3.2 liters (3.4 U.S. quarts or 2.8 British Imperial quarts); it was divided into 6 sextarii (sixths) which corresponded closely to modern pints. In the nineteenth century, the congius was used in British medicine and pharmacology as a name for the British Imperial gallon (4.546 09 liters).

cuartillo
a traditional Spanish unit of volume comparable to the liter or the English quart. The cuartillo equals 4 octavillos or 1/4 almude and contains 1.156 25 liters, which is about 1.222 U.S. liquid quart or 1.017 British imperial quart.

cubic centimeter (cm3 or cc)
the CGS unit of volume, equal to 10-6 cubic meter, 1 milliliter, or about 0.061 023 7 cubic inch.

cubic foot (ft3, cu ft, or cf)
a traditional unit of volume in English speaking countries. One cubic foot equals 1728 in3, 1/27 yd3, 0.028 316 85 m3, or 28.316 85 liters. The cubic foot also holds about 7.4805 U.S. liquid gallons or about 6.2288 British Imperial gallons.

cubic inch (in3 or cu in)
a traditional unit of volume in English speaking countries. One cubic inch equals 1/1728 = 5.787 037 x 10-4 ft3, 16.3871 cm3, 16.3871 milliliters, 0.5541 U.S. fluid ounce, or 0.5767 British Imperial fluid ounce.

cubic meter (m3)
the SI unit of volume, equal to 106 cm3, 1000 liters, 35.3147 ft3, or 1.307 95 yd3. A cubic meter holds about 264.17 U.S. liquid gallons or 219.99 British Imperial gallons.

cubic yard (yd3)
a traditional unit of volume in English speaking countries. One cubic yard equals 27 ft3, 46 656 in3, 0.764 555 m3, or 764.555 liters. A cubic yard holds about 201.97 U.S. liquid gallons or about 168.20 British Imperial gallons.

cup (c)
a traditional unit of volume used in recipes. One cup equals 1/2 (liquid) pint, or 8 fluid ounces. Technically, one cup equals exactly 14.4375 cubic inches or approximately 236.6 milliliters, not that anyone measures quite so precisely in the kitchen. American cooks use the same size cup for measuring both liquid and dry substances. In Canada, a cup is equal to 8 Imperial fluid ounces (13.8710 cubic inches or 227.3 milliliters). In Britain, cooks sometimes use a similar but larger unit called the breakfast cup, equal to 10 Imperial fluid ounces.

cusec
a traditional unit of flow equal to 1 cubic foot per second or about 28.317 liters per second.

dash (ds)
an informal unit of volume used in food and drink recipes. Originally the dash was usually a liquid measure, small but indefinite in amount, roughly 1/8 teaspoon or a little less. More recently it has been used as both a liquid and dry measure. Kitchen supply stores in the U.S. and other countries have begun selling sets of "minispoons" in which the dash spoon is designed to hold exactly 1/8 teaspoon, which is roughly 0.02 fluid ounce or 0.6 milliliter

deciliter (dl or dL)
a common metric unit of volume equal to 0.1 liter or 100 cubic centimeters. A deciliter contains 6.10237 cubic inches, 3.38140 U.S. fluid ounces, or 3.519 British fluid ounces. The deciliter is similar in size to the gill, an old English unit of volume.

degree (° or deg)
a unit measuring the hardness of water. Water is called "hard" if it contains a high concentration of mineral salts, especially calcium carbonate. This concentration can be expressed clearly in parts per million (ppm) or in milligrams per liter (mg/L). But starting in the mid-19th century, several uses of "degree" for water hardness became well established. In the U.S. and Britain, hardness is measured in Clark degrees, named for the scientist who devised the first reliable test for water hardness. The Clark degree is defined as 1 part of calcium carbonate per 70 000 parts of water; this is about 14.3 parts per million (ppm), 17.1 mg/L, or 1 grain per gallon (gpg, another popular measure of hardness). The French, properly decimal as always, used a degree equal to exactly 10 ppm, while the German degree was equivalent to 17.8 ppm.

degree (° or deg)
the percentage of alcohol, by volume, present in a mixture. In winemaking, for example, a 13° wine is 13% alcohol by volume (13% v/v). This unit is also called the degree Gay-Lussac (° GL) after the French chemist Joseph-Louis Gay-Lussac (1778-1850).

degree Baumé (°B or °Bé)
a unit of relative density, as read on a type of hydrometer invented by the French chemist Antoine Baumé (1728-1804). Two scales are used, depending on whether the liquid is lighter than water or heavier than water. For lighter liquids, the relative density d in degrees Baumé is related to specific gravity S by the formula d = (144.3 / S) - 144.3; for heavier liquids the formula is d = 144.3 - (144.3 / S).

dekaliter or decaliter (daL or dal)
a metric unit of volume equal to 10 liters and comparable to the English peck. The dekaliter is equal to about 2.641 72 U.S. liquid gallons, 1.135 10 U.S. pecks, or 2.199 69 British imperial gallons (1.099 85 British pecks). The symbol dkL sometimes used for this unit is incorrect.

demi-
a traditional prefix meaning 1/2. The prefix is derived from the Latin dimedius, meaning a cut in the middle of something.
demi [1]
a half bottle of wine (375 milliliters).
demi [2]
an informal French unit of volume for beer, generally equal to 250 milliliters (1/4 liter). The unit was originally a half pint (demipinte).

dessertspoon or dessertspoonful (dsp or dssp)
a unit of volume sometimes used in food recipes. The dessertspoon is equal to 2 teaspoons; this is roughly equivalent to 10 milliliters in the U.S. and 7 milliliters in Britain.

double
a traditional unit of volume for liquor equal to 2 shots. In the U.S., a double equals 2 fluid ounces or about 59.15 milliliters.

double magnum
a large wine bottle holding about 3 liters, 4 times the volume of a regular bottle. A double magnum is also called a jeroboam.

dram (dr)
a traditional unit of volume. See fluid dram.

drop (gtt)
a unit of volume used in pharmacy. Traditionally the drop was another name for a minim, a unit of volume equal to 1/60 fluid dram or 1/480 fluid ounce (about 0.0616 milliliter in the U.S., 0.0592 milliliter in Britain). Now that prescriptions are written in metric units, the pharmacist's drop is equal to exactly 0.05 milliliter (20 drops/ml). In hospitals, intravenous tubing is used to deliver medication in drops of various sizes ranging from 10 drops/ml to 60 drops/ml. The traditional abbreviation is from the Latin gutta, drop. Originally, gt was the symbol for a single drop, with gtt being the plural.

drop
a informal unit of volume used in recipes. According to some older kitchen references, 24 drops = 1/4 teaspoon; with U.S. definitions this makes the drop equal to 1/576 fluid ounce or about 0.051 milliliter, comparable to the pharmacist's drop (previous entry).

drought severity category (D)
a measure of drought severity developed by the U.S. National Drought Mitigation Center and used widely by other agencies in the U.S. Categories are denoted D0-D5, with higher numbers indicating more severe drought. A table is provided.

drum
a unit of volume sometimes used in the oil trade. The traditional standard drum of oil contains 55 U.S. gallons or about 208.198 liters. One 55-gallon drum equals 1.3095 barrels [2]. In the metric world, drums of 200 liters, 205 liters, and 208 liters are in use as substitutes for the traditional size.

dsp, dssp
symbols for the dessertspoon (2 teaspoons). See "dessertspoon" above.

EBC
abbreviation for European Brewing Commission, frequently used for a unit of turbidity equal to 4.08 NTU or FNU.

Engler degree
a unit of kinematic viscosity given by readings on an Engler viscometer. The reading is the time (in seconds) required for 200 milliliters of the liquid being tested to flow through the device. The conversion of Engler degrees to absolute units requires an appropriate table, but for liquids having a viscosity of 100 centistokes or more the Engler degree is roughly equal to 7.6 centistokes

fathom (fth or fath)
a traditional unit of distance equal to 2 yards or 6 feet (approximately 1.829 meters). The word comes from the Old English fæthm, meaning "outstretched arms", because a fathom is the distance between a man's outstretched fingertips. This is a generic unit that has been used in many cultures since ancient times. Other versions include the Spanish braza, the French toise, the German klafter, the Danish favn (6.18 feet or 1.88 meters), the Swedish famn (5.84 feet or 1.78 meters) and the Japanese ken. In England, the fathom was a common unit during Saxon times, and it continued to be used for many purposes through the medieval era. In fact, the length of the foot may have been defined, early in the twelfth century, specifically to assure that 1 foot = exactly 1/6 fathom. Today the fathom is used almost exclusively at sea, measuring water depth, the length of ships' cables, etc.

FAU
abbreviation for formazin attenuation unit, a unit of water turbidity. This unit is used to express turbidity measured by a nephelometer that measures directly the fraction of light transmitted through a water sample as compared to the fraction transmitted through a standard preparation of formazin. The procedure is specified by standard ISO 7027 of the International Organization for Standardization. See NTU for additional information on turbidity

fifth
a traditional U.S. unit of liquid volume equal to 4/5 quart, which is the same as 1/5 gallon. The fifth contains exactly 46.2 cubic inches, or about 757.084 milliliters. This unit is an American version of the traditional bottle.

filette
a half bottle of champagne (375 milliliters).

firkin (fir)
a traditional unit of volume equal to 1/4 barrel or 1/2 kilderkin. Since barrels are of various sizes, the capacity of a firkin varies. Based on the standard U.S. barrel of 31.5 gallons, a firkin would equal 7.875 gallons, 1.05 cubic feet, or about 29.81 liters. Traditional British barrels and firkins are larger; in the imperial system a firkin holds 1.445 cubic feet or 40.91 liters. The unit is of Dutch origin, and its name is based on the Dutch word vier for four.

flagon
a traditional unit of liquid volume, generally equal to the wine (or U.S. liquid) gallon (about 3.785 liters). A flagon is a large, narrow-necked pitcher or bottle.

flask
an old name for a bottle, now specialized to mean a narrow, flattened container for alcoholic beverages. Such flasks come in various sizes, often holding around 6 U.S. fluid ounces or 180 milliliters. The word is very old, appearing as flaska in Old High German and as flascon in Latin.

fluid dram or fluidram (fl dr)
a unit of volume in the traditional apothecary system, equal to 1/8 fluid ounce. This unit is usually called the fluid dram or fluidram to avoid confusion with the weight dram. The U. S. fluid dram contains about 0.225 586 cubic inches or 3.696 691 milliliters. In the British imperial system, the fluid dram is about 0.216 734 cubic inches or 3.551 633 milliliters.

fluid ounce (fl oz)
a traditional unit of liquid volume, called the fluid ounce to avoid confusion with the weight ounce. In the U. S. customary system there are 16 fluid ounces in a pint, so each fluid ounce represents 1.804 687 cubic inches or 29.573 531 milliliters. In the British Imperial system there are 20 fluid ounces in an imperial pint, so each fluid ounce represents about 1.733 871 cubic inches or 28.413 063 milliliters. A U.S. fluid ounce of water weighs just a bit more than one ounce avoirdupois; a British fluid ounce weighs exactly one ounce at a specified temperature and pressure.

fluid scruple
a traditional British unit of liquid volume equal to 1/3 fluidram or about 1.1839 milliliters.

FNU
abbreviation for formazin nephelometric unit, a unit of water turbidity equivalent to the NTU (nephelometric turbidity unit) used in the U.S. The symbol FNU, specified by the International Organization for Standardization in its standard ISO 7027, is widely used outside the U.S. See NTU.

foot of head (ft hd)
a traditional unit of water pressure used in plumbing and hydraulics. "Head" is short for "headwaters"; it refers to the depth of the water upstream from the point at which the pressure is measured. One foot of head is equivalent to a pressure of 0.433 lb/in2, 2.989 kilopascals (kPa), 29.89 millibars (mb), or 0.882 inches of mercury (in Hg).

foot per minute (ft/min or fpm)
a traditional unit of velocity or flow rate. One foot per minute equals exactly 30.48 cm/min, 5.08 mm/s, or 0.018 288 miles per hour.

fpm, fps
common abbreviations for foot per minute (ft/min) and foot per second (ft/s or ft/sec), traditional units of flow (see above).

French (Fg or Ch)
a unit of distance used for measuring the diameters of small tubes such as catheters, fiber optic bundles, etc. One French is equal to 1/3 millimeter (about 13.123 mils). The name and the symbol Ch refer to the Charrière gauge scale, which is often called the French scale.

fsw
symbol for "feet of seawater," a conventional unit of pressure. 1 fsw = 0.3048 meter of seawater (msw).

fuder
a traditional German unit of liquid volume. A "fuder" is a cartload. In most of the German states the traditional fuder held about 9 hectoliters (roughly 238 U.S. gallons), making the fuder about the same size as the British tun or the French wine tonneau. In the Mosel wine region of Germany, a fuder is now a metric unit equal to 10 hectoliters (1 cubic meter, or 264.17 U.S. gallons). In Austria, the traditional fuder was equal to 18.11 hectoliters (478.42 U.S. gallons), twice the size of the German unit. In Belgium today, the fuder (or foudre) is a metric unit equal to 30 hectoliters (792.52 U.S. gallons).

gallon (gal) [1]
a traditional unit of liquid volume, derived from the Roman galeta, which originally meant a pailful. Gallons of various sizes have been used in Europe ever since Roman times. In the United States, the liquid gallon is legally defined as exactly 231 cubic inches; this is equal to the old English wine gallon, which originated in medieval times but was not standardized until 1707, during the reign of Queen Anne. Some scholars believe the wine gallon was originally designed to hold 8 troy pounds of wine. The U. S. gallon holds 4 liquid quarts or exactly 3.785 411 784 liters; a U.S. gallon of water weighs about 8.33 pounds. American colonists were also familiar with the Elizabethan beer and ale gallon, which held 282 cubic inches (4.621 liters).

gallon (gal) [2]
a historic British unit of dry volume still used implicitly in the U.S. In the U.S., the term "gallon" is not used in dry measure, but if it were it would be equal to 1/2 peck, or 4 dry quarts, or 268.8025 cubic inches, or approximately 4.404 884 liters. This unit is the English corn or grain gallon, standardized during the reign of Elizabeth I in the sixteenth century. The earliest official definition of a dry gallon in Britain is a 1303 proclamation of Edward I, where the gallon is defined as the volume of 8 pounds of wheat; the current U.S. "gallon" contains about 7.5 pounds of wheat. Grain gallons have tended to be larger than liquid gallons throughout the history of British units, apparently because they were based on heaped rather than "struck" (leveled) containers. A container in which grain has been heaped above the top will hold as much as 25% more grain, and the traditional corn gallon is in fact 16.4% larger than the wine gallon.

gallon (gal) [3]
currently the British use a larger gallon than either of the American gallons. The Imperial Weights and Measures Act of 1824 established a new unit for all volumes, liquid or dry, replacing all the other gallons in previous use in Britain. The imperial gallon, designed to contain exactly 10 pounds of distilled water under precisely defined conditions, holds exactly 4.546 09 liters or approximately 277.4194 cubic inches. The imperial gallon equals 1.20095 U.S. liquid gallons (British wine gallons) or 1.03206 U.S. dry gallons (British corn gallons).

gallon (gal) [4]
a traditional unit of volume in Scotland equal to 4 Scots quarts. This is almost exactly 3 British Imperial gallons, 3.6 U.S. liquid gallons, or 13.63 liters.

galopin
a French name for a small glass of beer, typically 200 milliliters (about 6.76 U.S. fluid ounces).

gigaliter (GL or Gl)
a metric unit of volume equal to 109 liters or one million cubic meters. This is equivalent to 810.713 acre feet or 35.315 million cubic feet.

gill (gi)
a traditional unit of volume for liquids, especially wine and other alcoholic beverages. The gill is 1/4 pint. In the U. S. customary system, one gill is equal to 1/2 cup, 4 fluid ounces, 7.21875 cubic inches, or about 118.3 milliliters. In the British Imperial system, the gill equals 5 fluid ounces, 8.670 cubic inches, or about 137.7 milliliters. The unit is pronounced "jill", with a soft "g" sound. Its name comes a Latin word gillo for a small wine vessel.

glass
another name for the U.S. cup (236.6 milliliters). Doctors in the U.S. are fond of saying that everyone should drink 8 glasses of water a day, and this is the amount they have in mind for a glass.

glass
an informal unit of volume used in Australian pubs. In several states of Australia a glass of beer is usually 200 milliliters, but it is 235 milliliters in Queensland and 285 milliliters in Western Australia.

go
a traditional Japanese unit of liquid volume. One go is about 180.39 milliliters, 0.3812 U.S. pint, or 0.3174 British imperial pint.

gpf
symbol for gallons per flush, a specification sometimes found on toilets. 1 gpf = 3.785 liters per flush (Lpf). U.S. government regulations now require the use of low-flush toilets of 6.0 Lpf = 1.585 gpf or less.

gpg
customary symbol for grains per gallon (gr/gal), a traditional unit measuring the hardness of water. Water is "hard" if it contains dissolved minerals such as calcium or magnesium salts. 1 gpg is equivalent to about 17.118 milligrams per liter (mg/L). This unit is also called the Clark degree;

gpm, gps
customary symbols for gallons per minute (gal/min) and gallons per second (gal/s), traditional units for measuring the flow of liquids. 1 gpm equals about 3.785 41 liters per minute (L/min) if U.S. gallons are meant, or exactly 4.546 09 L/min if British imperial gallons are meant.

growler
a container of beer designed for carryout. In the U.S., a growler generally holds 1/2 gallon (about 1.89 liters).

handle
a traditional unit of volume for beer, used in pubs in the Northern Territory of Australia. A handle of beer is 285 milliliters (10 fluid ounces). Glasses of this size are called middies or pots in most Australian states, schooners in South Australia.

hectoliter (hL or hl)
a common metric unit of volume. The hectoliter equals 100 liters, 0.1 cubic meter, 26.417 U.S. liquid gallons, 21.999 British imperial gallons, or 3.5315 cubic feet.

hemina
a Roman unit of liquid volume, equal to 1/2 sextarius or about 265.6 milliliters (0.561 U.S. pint or 0.467 British Imperial pint).

hogshead (hhd)
a traditional unit of volume for liquids. Originally the hogshead varied with the contents, often being equal to 48 gallons of ale; 54 of beer; 60 of cider; 63 of oil, honey, or wine; or 100 of molasses. In the United States, a hogshead is defined to hold 2 barrels, or 63 gallons; this was the traditional British wine hogshead. It is equal to exactly 14 553 cubic inches, or about 8.422 cubic feet (238.48 liters). In the British imperial system, the hogshead equals 1/2 butt, or 52.5 imperial gallons (8.429 cubic feet, or 238.67 liters). Thus the British imperial and American hogsheads are almost exactly the same size. No one seems to know for sure how this unit got its unusual name.

hu
a traditional Chinese unit of liquid volume. The hu contains about 51.77 liters, 13.676 U.S. gallons, or 11.389 British imperial gallons.

imperial
a large wine bottle holding about 6 liters, 8 times the volume of a regular bottle. Also called a methuselah.

inch of water column (in WC)
a traditional unit of pressure, used in plumbing to describe both water and gas pressures. The conventional equivalent of one inch of water is 249.0889 pascals, which is 2.490 889 millibars, about 0.036 127 pounds per square inch (psi) or about 0.073 556 inches (1.868 32 millimeters) of mercury.

inch of water gauge (in wg or "wg)
another common name for the inch of water column. The word "gauge" (or "gage") after a pressure reading indicates that the pressure stated is actually the difference between the absolute, or total, pressure and the air pressure at the time of the reading.

jeroboam
a large wine bottle holding about 3 liters, 4 times the volume of a regular bottle. A jeroboam is sometimes called a double magnum.

jigger
a unit of volume for liquor, usually considered equal to 1.5 (U.S.) fluid ounces or 44.360 milliliters.

jug
an informal name for the Scots pint, a unit of volume equal to about 1.80 U.S. liquid quarts or 1.70 liters. Specifically, the jug of Stirling is the actual vessel (on display at the Stirling Museum) which was the legal standard for Scottish volume measurements prior to the introduction of the British Imperial units.

keddah
a traditional Egyptian unit of liquid volume also used in other parts of the Middle East. The keddah is equal to about 2.0625 liter (about 2.18 U.S. liquid quarts or 1.815 British imperial quarts).

keg
a traditional unit of volume or quantity, varying with the item contained in the keg. A keg of herring, for example, contains 60 fish. A keg of wine is frequently 12 U.S. gallons (about 45.42 liters), and a keg of beer is 1/2 barrel or 15.5 U.S. gallons (about 58.67 liters). "Keg" comes from an old Norse word for a small barrel.

kilderkin
an old British unit of volume equal to 1/2 barrel or 2 firkins. Based on the current British barrel, this would be 18 (imperial) gallons, which is about 2.9 cubic feet or 78 liters. Older kilderkins were generally in the range of 16-18 gallons. The word comes from a Dutch word for a small cask.

knot (kn or kt)
a unit of velocity equal to one nautical mile per hour. Knots are customarily used to express speeds at sea, including the speed of the ship as well as the speeds of the wind and of the current. The word comes from the former method of measuring a ship's speed, which involved use of a knotted cord called the log line. One knot equals about 1.1508 miles per hour, exactly 1.852 kilometers per hour, or 0.5143 meters per second. Since kt is the established symbol for the kilotonne, kn is the best choice as a symbol for the knot.

knot
an informal unit fo distance equal to the nautical mile.

köddi
a traditional Arabic unit of volume, equal to about 4/3 British imperial gallon or 7.58 liters.

koku
a traditional Japanese unit of volume, equal to about 180.391 liters (39.68 British imperial gallons or 6.37 cubic feet). The unit originated as an estimate of the amount of rice needed to feed a person for a year.

krina
a traditional unit of volume in Bulgaria, now expressed in the metric system as being equal to exactly 20 liters (4.40 British imperial gallons or 5.28 U.S. liquid gallons).

kulmet
a traditional Latvian unit of volume equal to about 10.93 liters (2.40 British imperial gallons or 2.89 U.S. liquid gallons). A similar Estonian unit, the külimet, equals about 11.48 liters (2.53 British imperial gallons or 3.03 U.S. liquid gallons).

lambda
a metric unit of volume equal to the cubic millimeter (mm3) or microliter (µL). The lambda has been used in chemistry in measuring very small samples. The symbol is the lower case Greek letter lambda.

ligula
a Roman unit of liquid volume equal to 1/48 sextarius or about 11.07 milliliters. The word literally means "a lick."

liter or litre (L or l)
the common metric unit of volume. The liter was originally defined to be the volume occupied by a kilogram of water, and the gram as the mass of a cubic centimeter of water. This would make the liter equal to exactly one cubic decimeter, that is, to the volume of a cube 0.1 meter (or 10 centimeters) on a side. Unfortunately, the physical objects constructed to represent the meter and kilogram disagreed slightly. As measured by the standard meter and standard kilogram, the standard liter turned out to be about 1.000 028 cubic decimeters. This discrepancy plagued the metric system for a long time. In 1901 an international congress accepted the discrepancy and formally defined the liter to be exactly 1.000 028 dm3. No one was particularly happy with such an awkward definition, and in 1964 the CGPM repealed the definition. In the SI, volumes are to be measured in cubic meters or power-of-ten multiples thereof, not in liters. However, the SI states that the liter "may be employed as a special name for the cubic decimeter." Throughout this dictionary, the liter is used as a name for exactly 1 cubic decimeter, 1000 cubic centimeters, or 0.001 cubic meter. In its renewed guise as the cubic decimeter, the liter is approximately 61.023 744 cubic inches. Compared to the customary volume units, the liter is a little more than a U. S. liquid quart (1.056 688 qt or 33.814 fluid ounces) but a little less than a U. S. dry quart (0.908 08 qt) or a British imperial quart (0.879 89 qt or 35.195 fluid ounces). Its name comes from a French volume unit, the litron, which was in turn derived from the Latin litra. Both the lower case letter l and the upper case L are accepted as symbols for the liter, but the U.S. Department of Commerce specifies that L be used, at least by businesses, to avoid confusion with the numeral 1. The unit is spelled liter in the U.S. and litre in Britain; there are many other spellings in various languages (see Spelling of Metric Units).

maf or Maf
a symbol for one million acre feet. This symbol, commonly used in reservoir management in the U.S., should be written Maf. 1 Maf = about 1.2335 billion (109) cubic meters

magnum
a traditional unit of volume for wine, generally equal to 2 bottles. This is now exactly 1.5 liters (about 2.114 U.S. quarts).

megaliter (Ml or ML)
a metric unit of volume equal to 1000 cubic meters. Commonly used in reservoir and water system management outside the U.S., the megaliter equals 264 172 U.S. gallons or 0.810 713 acre foot.

melchior
a huge bottle of champagne, holding about 18 liters.

methuselah
a large wine bottle holding about 6 liters, 8 times the volume of a regular bottle.

Mgd
an abbreviation for millions of gallons per day (Mgal/d), a unit used in reservoir management to express the rate at which water is withdrawn, or could be withdrawn, for drinking or for some other purpose. 1 Mgd equals approximately 3.785 43 megaliters per day, or 3785.43 cubic meters per day, or 133 681 cubic feet per day.

microliter (µl, µL, mcl, or mcL)
a metric unit of volume equal to 0.001 milliliter or 1 cubic millimeter (mm3). Microliters are used in chemistry and medicine to measure very small quantities of liquid. This unit has also been called the lambda.

middy
an informal unit of volume for beer used in many Australian pubs. A middy is generally 285 milliliters (or 10 British fluid ounces), larger than a pony but smaller than a schooner.

milliard
a unit of volume used by engineers to describe a large quantity of water. One milliard equals one cubic kilometer, which is 1 billion (109) cubic meters or about 810 767 acre feet.

milliliter (ml or mL)
a very common metric unit of volume. One milliliter equals 0.001 liter, exactly one cubic centimeter (cm3 or cc), or approximately 0.061 023 7 cubic inch or 16.231 U.S. minims (see below). The milliliter is used almost entirely for measuring the volumes of liquids, with solids being measured in cubic centimeters.

millimeter of water (mmH2O, mm WC, mm CE, mm WS)
a unit of pressure equal to the pressure exerted at the Earth's surface by a column of water 1 millimeter high. This is a small pressure, about 9.8067 pascals, 0.098 067 millibars, 0.03937 inch of water, or 0.204 pounds per square foot. The French symbol is mm CE (colonne d'eau), and the German symbol is mm WS (Wassersäule).

millimeter of water gauge (mm WG)
another common name for the millimeter of water column. The word "gauge" (or "gage") after a pressure reading indicates that the pressure stated is actually the difference between the absolute, or total, pressure and the air pressure at the time of the reading

miner's inch
a traditional unit of water flow in the western United States. The unit originally represented streamflow through an opening one inch (25.4 mm) square at a specified distance below the surface of the water; this distance varied from 4 to 6 inches. In Idaho, Kansas, Nebraska, New Mexico, North and South Dakota, Utah, and Washington the miner's inch is legally defined to equal 9 gallons per minute or 1.2 cubic feet per minute (about 34.07 liters per minute). In Arizona, California, Montana, Nevada, and Oregon the definition is 1.5 cubic feet per minute (42.48 L/min). In Colorado, the legal equivalent is 1.5625 cubic feet per minute (44.25 L/min). See also water inch.

minim (m or min)
a traditional unit of volume used for very small quantities of liquids. In pharmacy, the term drop traditionally meant the same thing as 1 minim. The minim is defined to be 1/60 fluid dram or 1/480 fluid ounce. The U. S. minim is equal to about 0.003 760 cubic inch or 61.610 microliters, while the British minim is equal to about 0.003 612 cubic inch or 59.194 microliters. As you might guess, the word comes from the Latin minimus, small.

msw
symbol for "meters of seawater," a conventional unit of pressure. The pressure exerted by seawater varies slightly with temperature and salinity, but for practical purposes the convention is that each meter imposes a pressure of 0.1 bar or 10 kilopascals (about 0.102 kilograms of force per square centimeter or 1.45 pounds per square inch). Sometimes the convention is that each meter is equivalent to 0.1 atmosphere (0.1013 bar), which is practically the same thing. In English units, 1 msw = 3.28 feet of seawater (fsw). Underwater pressure gauges are frequently calibrated in this unit.

mutchkin
a traditional Scottish unit of liquid volume. The mutchkin is about 15 British fluid ounces, which is about 426 milliliters or almost exactly 0.9 U.S. pint.
mwe

nebuchadnezzar
a huge wine bottle holding about 15 liters, 20 times the volume of a regular bottle.

nip
an informal unit of liquid volume. The term "nip" often means "a small amount," with no precise equivalent. In U.S. bartending, a nip is often taken to be 2 fluid ounces (about 59 milliliters). In Britain, a nip of spirits is considered to be 1/6 gill (about 22.95 milliliters or 0.776 U.S. fluid ounce); a nip of beer is 1/4 pint (the same as a gill, 4 fluid ounces or about 117.7 milliliters) or sometimes 1/3 pint (189.4 milliliters).

noggin
a traditional unit of liquid volume, used primarily in Ireland. Like the gill, the noggin is often taken to equal 1/4 pint; sometimes it is taken to be 1/2 pint.

NTU
abbreviation for nephelometric turbidity unit, a unit used in measuring water quality. Turbidity is an optical property: the scattering and absorption of light by solids suspended in water. In other words, water is turbid if you can't see through it. An instrument called a nephelometer (from a Greek word meaning "cloudy") measures turbidity directly by comparing the amount of light transmitted straight through a water sample with the amount scattered at an angle of 90° to one side; the ratio determines the turbidity in NTU's. The instrument is calibrated using samples of a standard solution such as formazin, a synthetic polymer. Drinking water should not have a turbidity above 1 NTU, although values up to 5 NTU are usually considered safe.This unit is also called the FNU (formazin nephelometric unit) in some countries..

ohm
a traditional German unit of liquid volume, no longer in use. The ohm, spelled aume in English, was generally equal to 1/6 fuder or roughly 150 liters (40 U.S. gallons).

oitavo
a traditional Portuguese unit of liquid volume comparable to 1/2 gallon in the U.S. system. The oitavo equals 1/32 fanega or about 1.73 liters (0.46 U.S. liquid gallon or 0.38 British imperial gallon).

oka or oke
a traditional unit of weight in Turkey and the eastern Mediterranean. The oka is approximately 2.8 pounds or 1.28 kilograms, but its size varied somewhat over the large area formerly included in the Turkish empire. The oka is also used sometimes as a unit of liquid volume, representing the volume (roughly 1.25 liters) occupied by an oka (weight) of water or wine.

osmole (Osm)
a unit of osmotic pressure used in physical chemistry, cell biology, and medicine. If chemical solutions are separated by a semipermeable membrane (a membrane that resists the passage of dissolved substances but permits the passage of the solvent, usually water), then the solvent will diffuse across the membrane to equalize the concentrations. This process is called osmosis. Solutions with higher concentrations of dissolved substances are said to have higher osmotic pressure than solutions having lower concentrations; thus the solvent moves from an area of low osmotic pressure to an area of higher osmotic pressure. One osmole is the osmotic pressure of a one molar solution (that is, a solution with a concentration of one mole per liter of solvent) of a substance that does not dissociate, such as sugar (glucose) in water. Osmotic pressure depends on the total number of dissolved particles, so for a substance that dissociates into two ions, such as ordinary salt (sodium chloride), a one molar solution has an osmotic pressure of 2 osmoles. In practice, most measurements are in milliosmoles (mOsm). Typical values range from 20 mOsm for fresh water through 290 mOsm for typical human blood plasma to 1010 mOsm for salt water from the open ocean.

ounce (oz or fl oz)
a traditional unit of liquid volume, also called the fluid ounce (fl oz).

pascal (Pa)
the SI unit of pressure. The pascal is the standard pressure unit in the MKS metric system, equal to one newton per square meter or one "kilogram per meter per second per second." Sounds impressive, but in traditional English terms a pascal is only 0.000 145 pounds per square inch (0.020 885 lbf/ft2 or 0.007 50 mmHg). Thus pressure is more commonly measured in kilopascals (kPa), with 1 kPa = 0.145 lbf/in2. Air pressure is also measured in hectopascals (hPa), with 1 hPa = 1 millibar. The unit is named for Blaise Pascal (1623-1662), French philosopher and mathematician, who was the first person to use a barometer to measure differences in altitude.

perm
a traditional unit of water vapor permeability, that is, the ability of a material to permit the passage of water vapor. If we want to keep things dry, we wrap them in something having low permeability. A material has a permeability of one perm if it allows transmission of one grain of water vapor per square foot of area per inch of mercury (inHg) of pressure difference per hour. The value depends somewhat on temperature, however. At 0 °C, one perm equals about 5.721 x 10-11 kilograms per square meter per pascal per second (kg/(m2·Pa·s)) or about 0.2060 mg/(m2·Pa·h); at room temperature the equivalent is about 5.745 x 10-11 kg/(m2·Pa·s). [The SI unit, kg/(m2·Pa·s), simplifies to seconds per meter (s/m).] The lower the perm value, the better the vapor barrier.

picoliter (pl or pL)
a metric unit of volume equal to 10-12 liter or 1000 cubic micrometers. Engineers at Eastman Kodak recently reported a technique for producing ink droplets as small as several picoliters.

picolo
a unit of volume for champagne, equal to 1/4 bottle (187.5 milliliters).

pin
a traditional British unit of volume, used for beer. A pin is very different from a pint: it is equal to 1/8 barrel or 4.5 imperial gallons (20.457 liters). There are 2 pins in a firkin.

pint (pt)
a traditional unit of volume equal to 1/2 quart. There are three different quarts in use in Britain and the United States, and hence there are three different pints: [i] the U. S. liquid pint, equal to exactly 28.875 cubic inches, 16 fluid ounces, or approximately 473.176 milliliters; [ii] the U. S. dry pint, equal to 33.600 cubic inches or approximately 550.611 milliliters; and [iii] the British imperial pint, equal to 20 British fluid ounces, 34.678 cubic inches or approximately 568.261 milliliters. The origin of the word pint is unclear. It may come from the Latin pincta, painted, referring to a marking at the one-pint level on a larger container.

pint (pt)
a traditional unit of volume in Scotland equal to 2 choppins or 4 mutchkins. The Scots pint varied with time and locality, but it was eventually standardized as the volume of the Stirling jug, a vessel holding about 104.2 cubic inches or 1.708 liters. This is almost exactly 3 Imperial pints or 3.6 U.S. liquid pints.

pint (pt)
a unit of volume used in South Australian pubs. A pint of beer is generally 425 milliliters in South Australia, or roughly 3/4 imperial pint (15 fluid ounces).

pipa
a traditional Portuguese unit of liquid volume, originally very similar in size to the English pipe (see next entry). The pipa has become a metric unit equal to exactly 500 liters, which is 0.5 cubic meter, 132.085 U.S. gallons, or 109.996 British imperial gallons.

pipe
like the butt, the pipe is a traditional unit of liquid volume generally equal to 2 hogsheads. In the U.S., this means a pipe equals 126 U.S.gallons, about 16.844 cubic feet or 476.96 liters. In Britain it's more complicated, because traditional British hogsheads were of different sizes depending on what they contained. The British pipe was usually used as a wine measure, but even different types of wine had different size pipes.

PN
a symbol for "nominal pressure," a measure used for rating piping, valves, fittings, etc. Nominal pressure is essentially the pressure rating of the piping system, measured in megapascals at a temperature of 20 °C (68 °F). (One megapascal equals approximately 145.038 pounds per square inch in traditional English units.) Industrial standards organizations, such as the American National Standards Institute (ANSI), set standards for pipes and fittings based on PN ratings; these standards specify in detail the size, composition, and strength of each component.

pony [1]
a small glass for liquor. In the U.S., a pony generally holds exactly 1 (U.S.) fluid ounce or about 29.6 milliliters. The word "pony" means a small horse, hence anything smaller than normal--in this case, a smaller shot glass.

pony [2]
a small glass for beer. In New South Wales, Victoria, South Australia, and Western Australia, a pony of beer holds 140 milliliters (about 5 British fluid ounces).

pony [3]
a small keg of beer. In the U.S., a pony keg holds 1/4 barrel or 7.75 U.S. gallons (about 29.34 liters).

pot [1]
a traditional unit of volume in many countries of Europe, roughly comparable to the liter or to the English quart. In Switzerland, the pot is now a metric unit equal to 1.5 liters. In Belgium, the pot is interpreted as 1.5 liters for dry quantities, but only 0.5 liters for liquids. The traditional pot is equal to 0.967 liters in Denmark and to 0.965 liters in Norway.

pot [2]
a unit of volume used in Australian pubs. A pot of beer is 285 milliliters in Queensland and Victoria, 575 milliliters in Western Australia.

pottle
a traditional unit of volume equal to 1/2 gallon. The unit's name is from the French potel, a type of bottle.

pound per square foot (lbf/ft2 or psf)
a traditional unit of pressure. 1 psf equals about 47.880 pascals (Pa), 0.478 80 millibars (mb), or 0.192 79 inch of water (in WC).

pound per square inch (lbf/in2 or psi)
a traditional unit of pressure. 1 psi equals 144 pounds per square foot (psf), 6.894 75 kilopascals (kPa), 68.9475 millibars (mb), 2.036 inches of mercury (in Hg), 27.7612 inches of water (in WC), or 70.5134 centimeters of water (cm H2O). See below for related notations such as "psig."

proof (prf)
a traditional unit of proportion used for measuring the strength of distilled liquors, including medicinal solutions of alcohol as well as alcoholic beverages such as whiskey. The proof rating of a liquor is the alcohol content of the liquid expressed as a percentage of the alcohol content of a standard mixture, called the proof liquor. In the United States, the proof liquor is legally defined so to contain exactly 50% alcohol measured by volume. As a result, the U. S. proof rating is equal to exactly twice the percentage of alcohol present, measured by volume. Thus "86 proof" means 43% alcohol. In Britain proof ratings are no longer used, but the former proof liquor contained 57.27% alcohol by volume. This means that 86 proof Scotch, in the U.S., was formerly 75 proof in Britain.

psi, psia, psid, psig
traditional symbols for pressure units used in hydraulics and plumbing. psi is a symbol for pound per square inch (see above). psig is a symbol for pound per square inch gauge; this means that the pressure has been read from a gauge which actually measures the difference between the pressure of the fluid and the pressure of the atmosphere. psia means pound per square inch absolute, which is the total pressure including the pressure of the atmosphere. psid, pound per square inch differential, is a symbol for a difference between two pressures, neither of which is atmospheric pressure. Corresponding symbols for pound per square foot (psf, etc.) are also used.

PSU or psu
an abbreviation for practical salinity unit, a standard measure of the salinity of seawater. The "unit" is actually a dimensionless (unitless) ratio obtained by measuring the conductivity of the water sample. Seawater of salinity 35 PSU has the same conductivity as a standard solution of potassium chloride (KCl) with a concentration of 3.243 56 % by mass; a sample of salinity 1 PSU would have conductivity 1/35 that of the standard solution. With this definition, measurements in PSU are very nearly the same as direct measurements of salt ion concentration in parts per thousand.

puncheon
a traditional unit of liquid volume. The puncheon is often reckoned as equal to 70 gallons. In the U. S. system that would be about 9.358 cubic feet or 264.98 liters; in the British imperial system it would be about 11.238 cubic feet or 308.34 liters. There are other versions of the unit; in one version a puncheon of wine equals 84 wine (or U.S.) gallons (roughly 308 liters); in another, a puncheon of beer equals 72 gallons (roughly 272.5 liters).

quart (qt) [1]
a traditional unit of volume, so-called because it equals exactly 1/4 (one quarter) of a gallon. However, there are several possible gallons to consider: [i] in the U. S. customary measure system for liquid volumes (such as milk, for example), one quart is exactly 57.75 cubic inches, 32 fluid ounces, or approximately 0.946 3529 liters; [ii] in the U. S. customary measure system for dry volumes (pecans or strawberries, for example), one quart is 67.201 cubic inches, or approximately 1.101 221 liters; [iii] finally, in the British imperial system, used for both liquid and dry commodities, one quart is 69.354 cubic inches, 40 fluid ounces, or exactly 1.136 5225 liters. In all cases, the quart equals 2 pints.

quart (qt) [2]
a unit of volume, smaller than the standard quart [1], used for measuring wine. Wine bottles have often been called "quarts," although they were smaller than standard quarts. In the U.S., wine was often measured by the champagne quart, which contains only 26 U.S. fluid ounces instead of 32. This is equivalent to about 46.92 cubic inches or approximately 768.912 milliliters. In Britain, wine was sold by the reputed quart. Following the establishment of Imperial measure, the reputed quart was fixed at 2/3 imperial quart, which is equivalent to exactly 26 2/3 fluid ounces, about 46.24 cubic inches, or 757.682 milliliters. These measures have mostly disappeared in favor of the international wine bottle, which contains exactly 750 milliliters.

quart (qt) [3]
a traditional unit of volume in Scotland equal to 2 Scots pints. This is almost exactly 3 British Imperial quarts, 3.6 U.S. liquid quarts, or 3.41 liters.

quarto [1]
a traditional Italian unit of volume, equal to about 73.6 liters or 2.60 cubic feet.

quarto [2]
a traditional Portuguese unit of volume, not related to the Italian quarto nor to the English quart. The Portuguese quarto equals 2 oitavos, which is about 3.46 liters or 0.92 U.S. gallon. There are 16 quartos in a fanega, 124 in a pipa

rehoboam
a large wine bottle holding about 4.5 liters, 6 times the volume of a regular bottle. The "h" is silent in English pronunciation.

salmanazar
a large wine bottle holding about 9 liters, 12 times the volume of a regular bottle.

saltspoon (ssp)
a unit of volume formerly used in U.S. food recipes. The saltspoon equals 1/4 teaspoon or about 1.2 milliliters.

schooner
an informal unit of liquid volume. A schooner is a large tumbler or drinking glass holding about 400 milliliters or 13.5 U.S. fluid ounces. Similarly, in Queensland, New South Wales, and the Northern Territory (Australia) a schooner of beer holds 425 milliliters. In South Australia, however, a schooner is only 285 milliliters.

schoppen
a traditional German unit of liquid volume, now interpreted most often as 250 milliliters (1/4 liter or about 8.45 U.S. fluid ounces).

schtoff
a traditional Russian unit of volume equal to 10 charki. This is equivalent to about 1.23 liters or 1.30 U.S. liquid quarts.

seah
an ancient Hebrew measure of both liquid and dry volume. The seah was equal to about 13.44 liters (about 3.55 U.S. liquid gallons or 2.96 British Imperial gallons).

seam
a traditional unit of volume. A seam of grain was 8 bushels: this would be equivalent to 290.95 liters based on the British Imperial bushel, or 281.91 liters based on the older U.S bushel. Take your pick. The Anglo-Saxon word "seam" meant the load of a pack animal. (The same word also came to mean the stitching of the packsaddle, and that's the origin of our other uses of the word today.) We don't know how large the seam was in Saxon times, but it was equal to 8 bushels at least by the end of the thirteenth century. The seam continued in use to the early nineteenth century, but in later years it was more often called a quarter [5].

sea mile
another name for the nautical mile.

second-day-foot (sdf)
a unit of volume for water sometimes used in U.S. hydrology. A second-day-foot is the volume of water accumulated in one day by a flow of one cubic foot per second; this is equal to exactly 86 400 cubic feet or about 2446.58 cubic meters. One second-day-foot is equivalent to approximately 1.9835 acre feet. Also known as the day-second-foot (dsf).

second-foot
an informal name for the cubic foot per second as a flow rate for water.

seidel
a traditional unit of liquid volume in Austria. The traditional seidel was equal to about 354 milliliters; this is about 12.0 U.S. fluid ounces or about 12.5 British fluid ounces. Today a seidel of beer in southern Germany and Austria is a small mug holding 300-500 milliliters, frequently the latter (1/2 liter or about 16.91 U.S. fluid ounces).

seven
a unit of volume for beer in New South Wales and some other sections of Australia. A seven of beer is a glass holding 200 milliliters (about 7 imperial fluid ounces). This volume is called a butcher in South Australia and a glass [3] many other parts of Australia.

sheng
a traditional unit of liquid volume in China. Like the Indian seer (see above), the sheng is a little more than a liter; 1.035 liter (1.094 U.S. quart) is one quoted equivalent.

shetland
a unit of volume for beer in Western Australia, equal to 115 milliliters (4 Imperial fluid ounces). This quantity is a smaller version of the 5-ounce pony; its name refers to Shetland ponies, small horses from the Shetland Islands north of Scotland.

sho
a traditional Japanese unit of liquid volume. The sho equals 1.8039 liter, which is 1.9061 U.S. quarts or 1.5872 British imperial qu

shot
a traditional unit of liquid volume. The term "shot" is often used informally to mean "a small serving." In the U.S. a shot is legally equal to one fluid ounce or 29.574 milliliters. However, many bartenders use larger shot glasses holding 1.25 fluid ounces (37.0 milliliters), and some shot glasses hold the same as a jigger: 1.5 fluid ounces or 44.4 milliliters.

snit
a U.S. unit of volume for liquor equal to 2 jiggers, 3 U.S. fluid ounces, or 88.7 milliliters. The origin of this unit is unknown.

split
a unit of volume for liquor equal to 4 jiggers, 6 U.S. fluid ounces, or 177.4 milliliters. The same name is used for a small wine bottle holding 1/4 the volume of a regular bottle; this would be about 187.5 milliliters. The unit appears to have originated as half the volume of a 12-ounce bottle of soda, which bartenders would split between two drinks.

spoonful
an informal unit of volume, sometimes an alternate name for the teaspoon.

stein
a German beer mug. Steins come in various sizes, but the most common size seems to be 1/2 liter (1.057 U.S pint or 0.880 British Imperial pint).

tablespoon or tablespoonful (tbsp, tblsp, or Tsp) [1]
a unit of volume used in food recipes. In the U.S., the tablespoon is equal to 1/2 fluid ounce; this is about 14.8 milliliters. In Canada, the traditional tablespoon is 1/2 Imperial fluid ounce (14.2 milliliters). In Britain, traditional tablespoons varied somewhat in size, and various older references give sizes in the range from 1/2 to 5/8 Imperial fluid ounce (14.2-17.6 milliliters). Under the metric system the tablespoon has become more or less standardized at 15 milliliters in Britain, Canada, and New Zealand, 20 milliliters in Australia. The U.S. tablespoon equals 3 teaspoons or 1/16 cup; the traditional British tablespoonful was often equal to 4 teaspoonfuls or 1/10 teacupful. The metric tablespoon equals 3 teaspoons (4 in Australia).

tablespoon or tablespoonful (tbsp, tblsp, or Tsp) [2]
a unit of volume used in bartending. U.S. bartenders use a tablespoon of 3/8 fluid ounce or 1/4 jigger; this is equivalent to about 11.1 milliliters.

teacupful
a unit of liquid volume used in British food recipes. The teacupful is the same volume as an Imperial gill: 5 fluid ounces, 8.670 cubic inches, or about 137.7 milliliters.

teaspoon or teaspoonful (tsp) [1]
a unit of volume used in food recipes. The U.S. teaspoon is equal to 1/3 tablespoon or 1/48 cup; this is equivalent to 1/6 fluid ounce, about 0.30 cubic inches, or approximately 4.9 milliliters. In Britain, a traditional teaspoonful in the kitchen was equal to 1/8 Imperial fluid ounce or approximately 3.55 milliliters, but the medical teaspoonful was usually 5 milliliters. In metric kitchens in Britain, Canada, Australia, and New Zealand, a teaspoonful is exactly 5 milliliters.

teaspoon or teaspoonful (tsp) [2]
a unit of volume used in bartending. U.S. bartenders use a teaspoon equal to 1/8 fluid ounce or 1/12 jigger; this is equivalent to about 3.7 milliliters.

to
a traditional Japanese unit of volume. The to equals 10 sho, which is about 18.039 liters, 3.968 British imperial gallons, or 4.765 U.S. liquid gallons.

tot
a unit of volume for liquor. Generally the term is used informally, with no fixed definition. However, in British pubs the usual understanding is that a tot is 1/6 gill; this is equivalent to 5/6 Imperial fluid ounce or about 23.7 milliliters.

tub
a wide, low container for liquids, generally not of any standard size. During the Prohibition era in the U.S. (1920-1933) liquor smugglers often carried their cargo in tubs holding 4 gallons (15.14 liters). In this they were following an old English tradition dating back at least to tea smugglers of the eighteenth century, who used similar 4-gallon tubs.

tumbler
another name for the U.S. cup.

tumblerful
another name for the breakfast cup, a unit of volume used in British food recipes.

tun
a unit of volume used for wine and other liquids. "Tun" is an old French word for a large cask used in shipping wine. Tuns of various sizes were used throughout the Middle Ages. More recently the tun has been regarded as equal to 2 butts or 252 U. S. gallons; this is equivalent to 33.6875 cubic feet or about 953.93 liters. See ton [3] and tonneau, above.

urna
a Roman unit of volume equal to 4 congii, 24 sextarii, or 1/2 amphora. This is equivalent to about 12.75 liters (3.37 U.S. liquid gallons or 2.80 British Imperial gallons). The Latin word urna was also used more broadly to mean a jug, giving rise to the English word urn.

viertel [1]
a traditional unit of volume in several European countries. Oddly, although the name means "quarter" in German the traditional viertel is not really 1/4 of any other unit. The Danish viertel equals 8 pots or about 7.74 liters (2.04 U.S. liquid gallons or 1.70 British imperial gallons). In Switzerland the viertel is 40 schoppen, which is exactly 15 liters (3.9626 U.S. liquid gallons or 3.3000 British imperial gallons).

viertel [2]
a unit of volume for wine in Austria, equal to exactly 1/4 liter (250 milliliters) or about 8.45 U.S. fluid ounces.

water inch
a traditional unit of water flow, supposed to equal the flow through a circular opening one inch in diameter, assuming the flow is caused only by gravity. However, this flow rate also depends on the pressure of the water above the opening. One estimate is 14 pints per minute or 2520 gallons per day (this is equivalent to 6.530 liters per minute); this estimate assumes the water level is constantly 1/12 inch (1 line) above the top of the opening. Another is 500 cubic feet per day, which is much larger: 3740 gallons per day or about 9.832 liters per minute. The latter estimate may depend on a mid-nineteenth century British engineering definition which required the hole to be centered 1 inch and 1 line below the water surface, placing the top of the opening 7/12 inch (7 lines) below the water level. See also miner's inch.

wine gallon
a former English unit of volume equal to 231 cubic inches. The wine gallon was adopted as the official gallon for liquid measurement in the United States, so now it is usually called the U.S. liquid gallon.

wineglass
an informal unit of volume used in U.S. bartending, equal to 4 (U.S.) fluid ounces or about 118.3 milliliters. This unit is the same as the traditional gill.

wineglassful
a unit of volume used in British food recipes. The wineglass holds 2.5 (British imperial) fluid ounces, 5 tablespoonfuls, 1/2 gill, or about 71.0 milliliters. One wineglassful is equal to 0.60 U.S. cup.

yard of ale
a traditional Scottish measure of volume. A yard of ale is roughly 2.5 pints (1.4 liters) served in a slender, yard-tall glass.

zak
a Dutch unit of volume, now interpreted as a metric unit equal to the hectoliter (100 liters). The hectoliter is equivalent to 26.417 U.S. gallons, 21.999 British imperial gallons, or 3.5315 cubic feet. This is a metric version of the British sack.