early 15c., "action of carrying, transportation," said to be from Old French portage and directly from Medieval Latin portaticum, though the meaning of these was "tax paid on entering a town," from Latin portare "to carry" (from PIE root *per- (2) "to lead, pass over"). The sense of "a break in a chain of water-communication over which goods, boats, etc. must be carried," also "the carrying of boats from one navigable water to another" is from 1690s, reinforced in U.S. and Canada by Canadian French.
