gallon

American  

[gal-uhn] / ˈgæl ən /

noun

• gallons
  plural

1. a common unit of capacity in English-speaking countries, equal to four quarts, the U.S. standard gallon being equal to 231 cubic inches (3.7853 liters), and the British imperial gallon to 277.42 cubic inches (4.546 liters). gal.

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gallon British  

/ ˈɡælən /

noun

1. Also called: imperial gallon.  a unit of capacity equal to 277.42 cubic inches. 1 Brit gallon is equivalent to 1.20 US gallons or 4.55 litres

2. a unit of capacity equal to 231 cubic inches. 1 US gallon is equivalent to 0.83 imperial gallon or 3.79 litres

3. (plural) great quantities

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gallon Scientific  

/ găl′ən /

1. A unit of liquid volume or capacity in the US Customary System equal to 4 quarts (3.79 liters).

2. See Table at measurement

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Other Word Forms

Noun Inflected Forms

• gallons
  plural

Etymology

Origin of gallon

First recorded in 1250–1300; Middle English galo(u)n, gallon, from Old North French galon, derivative from base of Medieval Latin gallēta “jug, bucket,” of uncertain origin

Compare meaning

How does gallon compare to similar and commonly confused words? Explore the most common comparisons:

• gallon vs. liter
• pint vs. gallon

Explanation

The gallon is a unit of measurement used for liquids such as gasoline, water, and milk in the United States. If your car’s tank is running on empty, then you better pull over and buy at least a few more gallons of gas. A gallon is equivalent to 4 quarts of liquid or 3.785 liters. The United States is one of the last countries to use this term. Though the gallon has roots in the British Imperial Units measurement system, the United Kingdom and most countries around the world have switched to the newer International System of Units.

Example Sentences

See Examples For:

gallon gallons

The waiver has let California obtain more fuel from Gulf of Mexico refineries, which has reduced the spread between the state’s gasoline prices and the national average by about 25 cents a gallon.

From The Wall Street Journal ● Aug. 14, 2026

The conflict has caused gas prices in the US to spike to above $4 a gallon, a painful hike to any US business that relies on transport.

From BBC ● Aug. 12, 2026

The average price of gasoline was $4.02 a gallon on Saturday, according to AAA.

From The Wall Street Journal ● Aug. 9, 2026

California Chevron stations have the highest prices of any brand, averaging $6.34 per gallon in May.

From Los Angeles Times ● Aug. 5, 2026

And three bottles of water—former cider jugs, holding one gallon each.

From "Z for Zachariah" by Robert C. O’Brien

Last year, Mexican authorities seized millions of gallons of contraband fuel in scores of railroad cars and trucks near Mexico’s border with Texas.

From Los Angeles Times ● Aug. 3, 2026

Renewable diesel volumes hit 3.8 million gallons a day, and ethanol production volumes averaged 4.7 million gallons a day.

From The Wall Street Journal ● Jul. 30, 2026

Their individual payloads of more than 1,000 gallons of water are then dumped onto the flames below.

From BBC ● Jul. 29, 2026

A 36-inch artery blew like a ruptured aorta, creating a sinkhole and sending 17 million gallons of water rushing through the streets.

From Los Angeles Times ● Jul. 25, 2026

“Every day they bestowed upon the statue of Bel twelve bushels of flour, forty sheep, and fifty gallons of wine.”

From "The Poisonwood Bible" by Barbara Kingsolver