Easton's Bible Dictionary
Three Hebrew words are thus rendered in the Authorized Version.
(1.) Hebrews mahsom' signifies a muzzle or halter or bridle, by which the rider governs his horse (Psalm 39:1).
(2.) Me'theg, rendered also "bit" in Psalm 32:9, which is its proper meaning. Found in 2 Kings 19:28, where the restraints of God's providence are metaphorically styled his "bridle" and "hook." God's placing a "bridle in the jaws of the people" (Isaiah 30:28; 37:29) signifies his preventing the Assyrians from carrying out their purpose against Jerusalem.
Noah Webster's New International Dictionary of the English Language
1. (n.) The head gear with which a horse is controlled, consisting of a headstall, a bit, and reins, with other appendages.
2. (n.) A restraint; a curb; a check.
3. (n.) The piece in the interior of a gun lock, which holds in place the tumbler, sear, etc.
4. (n.) A span of rope, line, or chain made fast as both ends, so that another rope, line, or chain may be attached to its middle.
5. (n.) A mooring hawser.
6. (v. t.) To put a bridle upon; to equip with a bridle; as, to bridle a horse.
7. (v. t.) To restrain, guide, or govern, with, or as with, a bridle; to check, curb, or control; as, to bridle the passions; to bridle a muse.
8. (v. i.) To hold up the head, and draw in the chin, as an expression of pride, scorn, or resentment; to assume a lofty manner; -- usually with up.