1. the metal mouthpiece of a bridle, with the adjacent parts to which the reins are fastened.
2. anything that curbs or restrains.
3. Machinery the cutting or penetrating part of various tools: a. the cutting portion of an axe or hatchet or the removable cutter in the plane, brace, etc. b. the movable boring or drilling part (in many forms) used in a carpenter's brace, a drilling machine, or the like.
4. the part of a key which enters the lock and acts on the bolt and tumblers.
-- verb (t) ( bitted, bitting )
5. to put a bit in the mouth of.
6. to curb; restrain.
7. to grind a bit on.
8. on the bit, (of a horse) restrained by pressure on the bit.
9. take the bit between one's teeth, a. to throw off control; rush headlong. b. to take the plunge, rejecting all restraint; throw one's energies into something.
[ME byt, OE bite action of biting]
-- bitless, adjective