With pins of adamant
And chains they made all fast. Milton.

He . . . did not care a pin for her. Spectator.

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.

To pin one's faith upon, to depend upon; to trust to.