gallon

American  

[gal-uhn] / ˈgæl ən /

noun

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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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

Example Sentences

Adjusted fuel expenses for the quarter were up 8.2% to $2.59 billion, while the average fuel price paid per gallon increased 6.9% to $2.62.

From MarketWatch • Apr. 8, 2026

But now that we’re back to $4 a gallon gasoline, and used car prices are rising, that could change.

From Barron's • Apr. 8, 2026

Nationwide diesel prices also notched a wartime high of $5.67 a gallon.

From The Wall Street Journal • Apr. 8, 2026

Jet fuel prices have surged more than $2 per gallon from before the conflict began and are now approaching $5 a gallon, the analysts say.

From The Wall Street Journal • Apr. 7, 2026

Nana motioned for me to grab a gallon of milk as we passed the dairy case.

From "We Are the Ants" by Shaun David Hutchinson