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.

Definitions of gallon
  1. noun
    United States liquid unit equal to 4 quarts or 3.785 liters
    synonyms: gal
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    type of:
    United States liquid unit
    a liquid unit officially adopted in the United States Customary System
  2. noun
    a British imperial capacity measure (liquid or dry) equal to 4 quarts or 4.545 liters
    synonyms: Imperial gallon, congius
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    type of:
    British capacity unit, Imperial capacity unit
    a unit of measure for capacity officially adopted in the British Imperial System; British units are both dry and wet
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