{To pin one's faith upon}, to depend upon; to trust to.
With pins of adamant And chains they made all fast.
--Milton.
2. Especially, a small, pointed and headed piece of brass or
other wire (commonly tinned), largely used for fastening
clothes, attaching papers, etc.
3. Hence, a thing of small value; a trifle.
He . . . did not care a pin for her. --Spectator.
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.
5. One of a row of pegs in the side of an ancient drinking
cup to mark how much each man should drink.
6. The bull's eye, or center, of a target; hence, the center.
[Obs.] ``The very pin of his heart cleft.'' --Shak.
7. Mood; humor. [Obs.] ``In merry pin.'' --Cowper.
8. (Med.) Caligo. See {Caligo}. --Shak.
9. An ornament, as a brooch or badge, fastened to the
clothing by a pin; as, a Masonic pin.
10. The leg; as, to knock one off his pins. [Slang]
{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.