before 1100; (noun) Middle Englishpinne,Old Englishpinn peg; cognate with Dutchpin,GermanPinne,Old Norsepinni; perhaps < Latinpinna feather, quill (see pinna); (v.) Middle Englishpinnen, derivative of the noun
repin, verb (used with object), repinned, repinning.
1. bolt, peg. 3. brooch.
a number assigned to an individual, used to establish identity in order to gain access to a computer system via an automatic teller machine, a point-of-sale terminal, or other device.
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.
acronym for personal identification number, 1981, from the first ref. used with redundant number.