1. United States liquid unit equal to 4 quarts or 3.785 litres
   "The car's fuel efficiency was measured in miles per gallon";
   - gal
    
2. A British imperial capacity measure (liquid or dry) equal to 4 quarts or 4.545 litres
   "The recipe called for an Imperial gallon of water";
   - Imperial gallon, congius

Derived forms: gallons

Type of: British capacity unit, Imperial capacity unit, United States liquid unit

Part of: barrel, bbl, bushel, firkin

Encyclopedia: Gallon, Thomas