Dictionary Definition
gallon
Noun
1 United States liquid unit equal to 4 quarts or
3.785 liters [syn: gal]
2 a British imperial capacity measure (liquid or
dry) equal to 4 quarts or 4.545 liters [syn: Imperial
gallon, congius]
User Contributed Dictionary
Noun
gallon (plural gallons) A unit of volume, equivalent to eight
pints or
 in the United Kingdom and Commonwealth of Nations exactly 4.54609 liters (an imperial gallon) and
 in the United States
 (in plural gallons; colloquial) A large quantity (of any
liquid).
 The pipe burst and gallons of water flooded into the kitchen.
Translations
A Gallon in the U.S. Customary System
 Finnish: gallona
A large quantity
Tatar
Noun
gallon gallon (a unit of volume).

 gallon benzin 3 dollarğa citsä = if gallon of gasoline reach 3 dollars'' http://www.azatliq.org/analysis/analysis/tb/2005/10/98df6ca5a34b414cb8f4386568594810.asp.
Declension
Extensive Definition
A gallon is a measure of volume. It is in current use in
the United
States and still has limited use in many other Englishspeaking
countries.
Historically the gallon has had many different
definitions, but there are three definitions in current use. These
are the U.S.
liquid gallon, the U.S. dry
gallon and the Imperial
(UK) gallon.
Definitions
 U.S. liquid gallon is legally defined as 231 cubic inches, and is equal to 3.785411784 litres (exactly) or about 0.13368 cubic feet. This is the most common definition of a gallon in the United States. The U.S. fluid ounce is defined as 1/128 of a U.S. gallon.
 U.S. dry gallon is oneeighth of a U.S. Winchester bushel of 2150.42 cubic inches, thus 268.8025 cubic inches (exactly) or 4.40488377086 litres (exactly). The U.S. dry gallon is less commonly used.
 Imperial (UK) gallon is legally defined as 4.54609 litres (≈ 277.42 cu in), which is about 1.2 U.S. liquid gallons. This definition is used in Commonwealth countries and Ireland, and is based on the volume of 10 pounds of water at 62 °F. (A U.S. liquid gallon of water weighs about 8.33 pounds at the same temperature.) The Imperial gallon is no longer legal, in the United Kingdom, for trade or public administration purposes, but it is used colloquially (and in advertising) for fuel consumption figures in miles per gallon.
The Imperial gallon continues to be used as a
unit of measure for fuel in Antigua
and Barbuda, Belize, Burma, Grenada, Guyana, Sierra Leone
and the United
Arab Emirates.
The word has also been used as translation for
several foreign units of the same magnitude.
Subdivisions
The gallons in current use are subdivided into eight pints or four quarts. Pints are further subdivided into fluid ounces and liquid gallons are also subdivided into 32 gills, i.e. a quarter of a pint. The subunits of pint and fluid ounce, despite having the same name in both Imperial and U.S. units, differ in volume and are therefore not interchangeable.The Imperial fluid ounce
is defined as 1/160 of an Imperial gallon.
History
At one time, the volume of a gallon depended on what was being measured, and where it was being measured. But, by the end of the 18th century, three definitions were in common use: The corn gallon, or “Winchester gallon”, of about 268.8 cubic inches (≈ 4.405 L),
 the wine gallon, or “Queen Anne’s gallon”, which was 231 cubic inches (≈ 3.79 L), and
 the ale gallon of 282 cubic inches (≈ 4.62 L).
The corn or dry gallon was used in the United
States until recently for grain and other dry commodities. It is
one eighth of the (Winchester) bushel, originally a
cylindrical measure of 18½ inches in diameter and 8 inches
depth. That made the dry gallon 9¼²·π in³ ≈ 268.80252 cubic
inches. The bushel, which like dry quart and pint still sees some
use, was later defined to be 2150.42 cubic inches exactly, making
its gallon 268.8025 cubic inches exactly (4.40488377086 L).
In previous centuries there had been a corn gallon of around 271 to
272 cubic inches.
The wine, fluid, or liquid gallon is the standard
U.S. gallon since the early 19th century. The wine gallon, which
some sources relate to the volume occupied by eight medieval
merchant
pounds of wine, was at one time defined as the volume of a
cylinder six inches deep and seven inches in diameter, i.e. 6·3½²·π
≈ 230.90706 cubic inches. It had been redefined during the reign of
Queen
Anne, in 1706, as 231 cubic inches exactly (3 in × 7 in × 11
in), which is the result of the earlier definition with π approximated to
22⁄7. Although the wine gallon had been used for centuries for
import duty purposes there was no legal standard of it in the
Exchequer
and a smaller gallon (224 cu in) was actually in use, so
this statute became necessary. It remains the U.S. definition
today.
The original ratio between corn and wine gallon
is 9¼²:6·3½² = 1369:1176, but 268.8:231 is exactly 64:55 or ca.
13:11. This approximation is still applicable, although the ratio
of 1.164115646 slightly changed to 1.163647186 with current
definitions (268.8025:231 = 107521:92400 ≈ 1344:1165). In some
contexts it is or was necessary to disambiguate between those two
U.S. gallons, so “liquid” or “fluid” and “dry” respectively are
then added to the name.
In 1824, Britain adopted a close approximation to
the ale gallon known as the Imperial gallon and abolished all other
gallons in favour of it. Inspired by the kilogramlitre relationship,
the Imperial gallon was based on the volume of 10 pounds of
distilled water weighed in air with brass weights with the
barometer standing at 30 inches of
mercury and at a temperature of 62 °F. In 1963,
this definition was refined as the space occupied by 10 pounds of
distilled water of density 0.998859 grams per millilitre weighed in
air of density 0.001217 g/mL against weights of density 8.136 g/mL.
This works out at approximately 4.5460903 L (277.4416
cu in). The metric definition of exactly 4.54609 cubic
decimetres (also 4.54609 L after the litre was redefined in 1964,
ca. 277.419433 cu in) was adopted shortly afterwards in
Canada; for several years, the conventional value of 4.546092 L was
used in the United Kingdom, until the Canadian convention was
adopted in 1985.
Before and into the 19th century there were also
several other gallons in use, with varying definitions. These are
summarized in the table below. During some eras, the gallon was
based on an exact conversion with a linear measure cubed. Other
eras, the gallon was based on a rational approximation to the
volume of a cylinder that could be used as a standard container,
such as a basket, barrel, or jar. Other definitions were based on
the density of a commodity, occasionally water, but more often a
more marketable good such as wine or oats. Given these options and
the variety of cultures that have used the gallon, it is not
surprising that the exact value has drifted over the
centuries.
Examples of gallons
References
See also
gallon in Belarusian (Tarashkevitsa):
Галён
gallon in Bulgarian: Галон
gallon in Czech: Galon
gallon in Danish: Gallon
gallon in German: Gallone
gallon in Spanish: Galón (unidad)
gallon in Esperanto: Galjono
gallon in French: Gallon
gallon in Galician: Galón
gallon in Korean: 갤런
gallon in Croatian: Galon
gallon in Italian: Gallone
gallon in Hebrew: גלון
gallon in Hungarian: Gallon
gallon in Dutch: Gallon
gallon in Japanese: ガロン
gallon in Norwegian: Gallon
gallon in Norwegian Nynorsk: Gallon
gallon in Polish: Galon (miara)
gallon in Portuguese: Galão
gallon in Romanian: Galon
gallon in Russian: Галлон
gallon in Simple English: Gallon
gallon in Slovak: Galón
gallon in Slovenian: Galona
gallon in Finnish: Gallona
gallon in Swedish: Gallon
gallon in Thai: แกลลอน
gallon in Vietnamese: Gallon
gallon in Chinese:
加仑