personal identification number
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n., v. pinned, pin•ning. n.
1. a small, slender, often pointed piece of metal, wood, etc., used as a fastener or support.
2. a short, slender piece of wire with a point at one end and a head at the other, for fastening things together.
3. any of various forms of fasteners, badges, or ornaments consisting essentially or partly of a penetrating wire or shaft (often used in combination): a fraternity pin; a tiepin.
a. a short metal rod, as a linchpin, driven through holes in adjacent parts, as a hub and an axle, to keep the parts together.
b. a short cylindrical rod or tube, as a wrist pin or crankpin, joining two parts so as to permit them to move in one plane relative to each other.
5. the part of a cylindrical key stem entering a lock.
8. a peg, nail, or stud marking the center of a target.
9. any one of the rounded wooden clubs set up as the target in tenpins, ninepins, duckpins, etc.
10. Golf. the pole, with flag, which identifies a hole; flagstick.
11. Informal. a human leg.
12. peg (def. 4).
13. Wrestling. a fall.
14. Naut. belaying pin.
15. a very small amount; a trifle.
16. a pin-shaped connection, as the terminals on the base of an electron tube or the connections on an integrated circuit.v.t.
17. to fasten or attach with or as with a pin or pins.
18. to hold fast in a spot or position (sometimes fol. by down).
19. to give one's fraternity pin to (a young woman) as a pledge of one's attachment.
20. Wrestling. to secure a fall over one's opponent.
21. pin down, to force (someone) to deal with a situation or to come to a decision.Idioms:
pin something on someone, Informal. to ascribe the blame or guilt for something to a person.
[before 1100; Middle English pinne, Old English pinn peg; c. Dutch pin, German Pinne, Old Norse pinni; perhaps < Latin pinna feather, quill]
an identification number assigned to an individual to gain access to a computer system via an automated-teller machine, a point-of-sale terminal, or other device.