Definition of gallon
- gallon Noun A unit of volume, equivalent to eight pints
- gallon Noun exactly 4.54609 liters; an imperial "gallon"
- gallon Noun 231 cubic inches or approximately 3.785 liters for liquids (a "U.S. liquid "gallon")
- gallon Noun one-eighth of a U.S. bushel or approximately 4.405 liters for dry goods (a "U.S. dry "gallon").
- gallon Noun A large quantity (of any liquid).