LOCK, n. [L. floccus, Eng. lock.]

1. Lock, in its primary sense, is any thing that fastens; but we now appropriate the word to an instrument composed of a spring, wards, and a bolt of iron or steel, used to fasten doors, chests and the like. The bolt is moved by a key.

2. The part of a musket or fowling-piece or other fire-arm, which contains the pan, trigger, &c.

3. The barrier or works of a canal, which confine the water, consisting of a dam, banks or walls, with two gates or pairs of gates, which may be opened or shut at pleasure.

4. A grapple in wrestling.

5. Any inclosure.

6. A tuft of hair; a plexus of wool, hay or other like substance; a flock; a ringlet of hair.

A lock of hair will draw more than a cable rope.

Lock of water, is the measure equal to the contents of the chamber of the locks by which the consumption of water on a canal is estimated.