/gal"euhn/ , n.
a common unit of capacity in English-speaking countries, equal to four quarts, the U.S. standard gallon being equal to 231 cubic inches (3.7853 liters), and the British imperial gallon to 277.42 cubic inches (4.546 liters). Abbr.: gal.
[ 1250-1300; ME galo ( u ) n, gallon galon, deriv. from base of ML galleta jug, bucket, of uncert. orig. ]