Pin

1. a small, slender, often pointed piece of wood, metal, etc., used to fasten, support, or attach things. 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 or ornaments consisting essentially or partly of a pointed or penetrating wire or shaft (often used in combination): a jeweled pin. 4. a badge having a pointed bar or pin attached, by which it is fastened to the clothing: a fraternity pin. 5. Machinery. a short metal rod, as a linchpin, driven through holes in adjacent parts, as a hub and an axle, to keep the parts together. 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. a short axle, as one on which a pulley rotates in a block. 6. the part of a cylindrical key stem entering a lock. 7. a clothespin. 8. a hairpin. 9. rolling pin. 10. a peg, nail, or stud marking the center of a target. 11. Bowling. any one of the rounded wooden clubs set up as the target in tenpins, ninepins, duckpins, etc. 12. Golf. the flag staff which identifies a hole. 13. any of the projecting knobs or rails on a pinball machine that serve as targets for the ball. 14. Informal. a human leg. 15. Music. peg (def 5). 16. Wrestling. a fall. 17. Nautical. an axle for a sheave of a block. belaying pin. 18. Carpentry. a tenon in a dovetail joint; dovetail. 19. a very small amount; a trifle: Such insincere advice isn't worth a pin. 20. Chess. the immobilization of an enemy piece by attacking with one's queen, rook, or bishop. 21. Electronics. a pin-shaped connection, as the terminals on the base of an electron tube or the connections on an integrated circuit.