turnpike n.

late Old English turnian "to rotate, revolve," in part also from Old French torner "to turn away or around; draw aside, cause to turn; change, transform; turn on a lathe" (Modern French tourner), both from Latin tornare "to polish, round off, fashion, turn on a lathe," from tornus "lathe," from Greek tornos "lathe, tool for drawing circles," from PIE root *tere- (1) "to rub, turn." Transitive sense in English is from c. 1300. Related: Turned; turning.

Use in expression to turn (something) into (something else) probably retains the classical sense of "to shape on a lathe." To turn up "arrive, make an appearance" is recorded from 1755. Turn about "by turns, alternately" is recorded from 1640s. To turn (something) loose "set free" is recorded from 1590s. Turn down (v.) "reject" first recorded 1891, American English. Turn in "go to bed" is attested from 1690s, originally nautical. To turn the stomach "nauseate" is recorded from 1620s. To turn up one's nose as an expression of contempt is attested from 1779.

Turning point is attested by 1640s in a figurative sense "point at which a decisive change takes place;" literal sense "point on which a thing turns; point at which motion in one direction ceases and that in another or contrary direction begins" is from 1660s.

early 13c., pik, pyk, "pointed tip or spike on a staff, pole, weapon, etc.," collateral (long-vowel) form of pic (source of pick (n.1)), from Old English piic "pointed object, pickaxe," which is perhaps from a Celtic source (compare Gaelic pic "pickaxe," Irish pice "pike, pitchfork"). The word probably has been influenced by, or is partly from, Old French pic "sharp point or spike," itself perhaps from Germanic (see pike (n.1)), Old Norse pic, and Middle Dutch picke, pecke. Pike, pick (n.1), and pitch (n.1) formerly were used indifferently in English.

From c. 1400 as "a sharp, pointed mountain or summit." The pike position in diving, gymnastics, etc., is attested by 1928, perhaps on the notion of "tapering to a point."

"highway," 1812 shortening of turnpike.