early 15c., "spiked road barrier used for defense," from turn + pike (n.2) "shaft." Sense transferred to "horizontal cross of timber, turning on a vertical pin" (1540s), which were used to bar horses from foot roads. This led to the sense of "barrier to stop passage until a toll is paid" (1670s). Meaning "road with a toll gate" is from 1748, shortening of turnpike road (1745).
c. 1300, gate "a going or walking, departure, journey," earlier "way, road, path" (c. 1200), from a Scandinavian source (compare Old Norse gata "way, road, path"), from Proto-Germanic *gatwon "a going" (source also of Old High German gazza "street," German Gasse "a way, road," Gothic gatwo), perhaps from PIE *ghe- "to release, let go." Meaning "manner of walking, carriage of the body while walking" is from mid-15c. Modern spelling developed before 1750, originally in Scottish. Related: Gaited.