gallon /ˈɡalən
/ ▸ noun 1 British English (also imperial gallon) a unit of liquid or dry capacity equal to eight pints or 4.55 litres. ▪ US English a unit of liquid capacity equal to 3.79 litres.
2 (gallons of) informal a large volume of something: gallons of fake blood.
– ORIGIN Middle English: from Anglo-Norman French galon, from the base of medieval Latin galleta, galletum ‘pail, liquid measure’, perhaps of Celtic origin.