Meaning

noun United States liquid unit equal to 4 quarts or 3.785 liters

noun a British imperial capacity measure (liquid or dry) equal to 4 quarts or 4.545 liters

originFrom Middle English gallon, galoun, galun, from Old Northern French galun, galon (“liquid measure”) (compare Old French jalon), from Late Latin galum, galus (“measure of wine”), from Vulgar Latin *galla (“vessel”), possibly from Gaulish *galla, ultimately from Proto-Indo-European *kel- (“goblet”). Cognate with Ancient Greek κύλιξ (kúlix, “cup”), Sanskrit कलश (kalaśa, “jar, pitcher; measure of…

Etymology from Wiktionary, CC BY-SA 3.0