gallon
Americannoun
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gallons
plural
noun
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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
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a unit of capacity equal to 231 cubic inches. 1 US gallon is equivalent to 0.83 imperial gallon or 3.79 litres
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(plural) great quantities
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A unit of liquid volume or capacity in the US Customary System equal to 4 quarts (3.79 liters).
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See Table at measurement
Other Word Forms
Noun Inflected Forms
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:
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.
Vocabulary lists containing gallon
Measurement and Data, List 2
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"How Do We Use Water?"
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Cormac McCarthy's "The Road"
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
That helps explain why voters might be aggravated and still surprised when they see, for example, a $5 price tag on a gallon of milk.
From The Wall Street Journal ● Oct. 8, 2026
Diesel hit a national average record of $6.528 a gallon in September, according to energy pricing specialists OPIS.
From The Wall Street Journal ● Oct. 8, 2026
The president of the American Farm Bureau Federation says “every cent per gallon matters” when you run a fleet of grain trucks.
From MarketWatch ● Oct. 7, 2026
Singh now yearns for prewar fuel prices of $4 per gallon, when filling up the tank cost $1,200.
From Los Angeles Times ● Oct. 7, 2026
He thought of the gallon jugs of bottled water his dad had carefully packed in the camper.
From "Earthquake Terror" by Peg Kehret
For example, Rainmaker's 19 million gallons equates to around 0.01 inch of rain across 100 square miles.
From BBC ● Oct. 7, 2026
The company claims it produced 19 million US gallons of water in the sky in three hours.
From BBC ● Oct. 7, 2026
Transport loads are the cheapest way to buy dyed diesel, he said, with maybe 7,000 to 7,400 gallons per delivery.
From MarketWatch ● Oct. 6, 2026
Hyperion failed in 2021 after human error and equipment failure flooded the plant, eventually pouring 17 million gallons of sewage into the ocean.
From Los Angeles Times ● Oct. 2, 2026
“An average tree will give twenty gallons in a season,” Mr. Chris said.
From "Miracles on Maple Hill" by Virginia Sorensen
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
