the standard British gallon, equal to 4.546 liters or about 11⁄5 U.S. gallons
imperial gallon in American English
noun
a British gallon equivalent to 11⁄5 U.S. gallons, or 277.42 cubic inches
Word origin
[1830–40]This word is first recorded in the period 1830–40. Other words that entered Englishat around the same time include: nationalism, rococo, showcase, stroboscope, walkover