1530s, "end point of a race," of uncertain origin. It appears once before this (as gol), in a poem from early 14c. and with an apparent sense of "boundary, limit." Perhaps from Old English *gal "obstacle, barrier," a word implied by gælan "to hinder" and also found in compounds (singal, widgal). That would make it a variant or figurative use of Middle English gale "a way, course." Also compare Old Norse geil "a narrow glen, a passage." Or from Old French gaule "long pole, stake," which is from Germanic. Sports sense of "place where the ball, etc. is put to score" is attested from 1540s. Figurative sense of "object of an effort" is from 1540s.
updated on March 25, 2015