Definition of gallon in US English:



  • 1US A unit of liquid capacity equal to 3.79 liters.

    1. 1.1British A unit of liquid or dry capacity equal to four quarts or 4.55 liters.
  • 2gallons ofinformal A large volume of something.

    ‘gallons of fake blood’
    • ‘Rather than wasting multiple gallons of energized water I should think it would be profitable, if not philanthropic, to bottle it and take it to market.’
    • ‘Those stars join a list of past celebrity sliming victims during the popular ritual in which gallons of slime rain down on someone during the festivities.’
    • ‘Just as well we're in the country here, with a good breeze and gazillions of gallons of fresh air to sweep it up.’
    • ‘What do a few buckets of waste mean anyway, in the grand scheme of things as you bob up and down atop gazillions of gallons of seawater?’
    • ‘A large aquarium was pulled over and smashed, sending gallons of water cascading over the floor.’
    • ‘A plethora of massive pipes keep draining millions of gallons of radioactive water into the sea with high amount of low-level radiation.’


Middle English: from Anglo-Norman French galon, from the base of medieval Latin galleta, galletum ‘pail, liquid measure’, perhaps of Celtic origin.