Pin hole

Pin Pin, n. [OE. pinne, AS. pinn a pin, peg; cf. D. pin, G. pinne, Icel. pinni, W. pin, Gael. & Ir. pinne; all fr. L. pinna a pinnacle, pin, feather, perhaps orig. a different word from pinna feather. Cf. {Fin} of a fish, {Pen} a feather.] 1. A piece of wood, metal, etc., generally cylindrical, used for fastening separate articles together, or as a support by which one article may be suspended from another; a peg; a bolt. [1913 Webster]

With pins of adamant And chains they made all fast. --Milton. [1913 Webster]

2. Especially, a small, pointed and headed piece of brass or other wire (commonly tinned), largely used for fastening clothes, attaching papers, etc. [1913 Webster]

3. Hence, a thing of small value; a trifle. [1913 Webster]

He . . . did not care a pin for her. --Spectator. [1913 Webster]

4. That which resembles a pin in its form or use; as: (a) A peg in musical instruments, for increasing or relaxing the tension of the strings. (b) A linchpin. (c) A rolling-pin. (d) A clothespin. (e) (Mach.) A short shaft, sometimes forming a bolt, a part of which serves as a journal. See Illust. of {Knuckle joint}, under {Knuckle}. (f) (Joinery) The tenon of a dovetail joint. [1913 Webster]

5. One of a row of pegs in the side of an ancient drinking cup to mark how much each man should drink. [1913 Webster]

6. The bull's eye, or center, of a target; hence, the center. [Obs.] ``The very pin of his heart cleft.'' --Shak. [1913 Webster]

7. Mood; humor. [Obs.] ``In merry pin.'' --Cowper. [1913 Webster]

8. (Med.) Caligo. See {Caligo}. --Shak. [1913 Webster]

9. An ornament, as a brooch or badge, fastened to the clothing by a pin; as, a Masonic pin. [1913 Webster]

10. The leg; as, to knock one off his pins. [Slang] [1913 Webster]

{Banking pin} (Horol.), a pin against which a lever strikes, to limit its motion.

{Pin drill} (Mech.), a drill with a central pin or projection to enter a hole, for enlarging the hole, or for sinking a recess for the head of a bolt, etc.; a counterbore.

{Pin grass}. (Bot.) See {Alfilaria}.

{Pin hole}, a small hole made by a pin; hence, any very small aperture or perforation.

{Pin lock}, a lock having a cylindrical bolt; a lock in which pins, arranged by the key, are used instead of tumblers.

{Pin money}, an allowance of money, as that made by a husband to his wife, for private and personal expenditure.

{Pin rail} (Naut.), a rail, usually within the bulwarks, to hold belaying pins. Sometimes applied to the {fife rail}. Called also {pin rack}.

{Pin wheel}. (a) A contrate wheel in which the cogs are cylindrical pins. (b) (Fireworks) A small coil which revolves on a common pin and makes a wheel of yellow or colored fire. [1913 Webster]