Definition of "gallon" in English

noun

1. A unit of volume, equivalent to eight pints

2. (British, Canada) exactly 4.54609 liters; an imperial gallon

3. (US) 231 cubic inches or approximately 3.785 liters for liquids (a "U.S. liquid gallon")

4. (US) one-eighth of a U.S. bushel or approximately 4.405 liters for dry goods (a "U.S. dry gallon").

5. (in the plural, informal) A large quantity (of any liquid).

   • The pipe burst and gallons of water flooded into the kitchen.