c.1420, "spiked road barrier used for defense," from
turn +
pike (2) "shaft." Sense transf. to "horizontal cross of timber, turning on a vertical pin" (1547), which were used to bar horses from foot roads. This led to the sense of "barrier to stop passage until a toll is paid" (1678). Meaning "road with a toll gate" is from 1748, shortening of
turnpike road (1745).