Etymology
1. late O.E.
pinn "peg, bolt," from P.Gmc.
*penn- "jutting point or peak" (cf. O.N.
pinni "peg, tack," M.Du.
pin "pin, peg," O.H.G.
pfinn, Ger.
Pinne "pin, tack") which may be via L.
pinna "wing, feather," also used for "pointed peak," from PIE
*bend- "something protruding." The modern slender wire pin is first attested by this name c.1380. Transferred sense of "leg" is recorded from 1530. The verb is recorded from c.1300; sense of "to hold someone or something down so he or it cannot escape" is attested from 1740.
Pin-up (adj.) is from 1941 (first in ref. to Dorothy Lamour); the noun is recorded from 1943.
Pinwheel is from 1696, "a wheel in the striking train of a clock in which pins are fixed to lift the hammer;" fireworks sense is from 1869.
Pinhead "person of small intelligence" is first attested 1896.
Pin-stripe is attested from 1896.
Pin-money "annual sum allotted to a woman for personal expenses on dress, etc." is attested from 1621.
2. Etymology tree
3. Proto-Germanic *pinnaz
4. Proto-West Germanic *pinn
5. Old English pinn
6. Middle English pinne
7. English pin
8. From Middle English pinne, from Old English pinn (“pin, peg, bolt”), from Proto-Germanic *pinnaz, *pinnō, *pint- (“protruding point, peak, peg, pin, nail”), from Proto-Indo-European *bend- (“protruding object, pointed peg, nail, edge”). Related to pen (“enclosure”).
9. Cognate with Dutch pin (“peg, pin”), Low German pin, pinne (“pin, point, nail, peg”), German Pinn, Pinne (“pin, tack, peg”), Bavarian Pfonzer, Pfunzer (“sharpened point”), Danish pind (“pin, pointed stick”), Norwegian pinn (“stick”), Swedish pinne (“peg, rod, stick”), Icelandic pinni (“pin”). More at pintle.
10. No relation to classical Latin pinna (“fin, flipper, wing-like appendage, wing, feather”), which was extended to mean "ridge, peak, point" (compare pinnacle), and often confused with Latin penna (“wing, feather”). More at feather and pen (Etymology 3). See: Swedish '
pinne'.