Bit. n.s. [bıꞇol, Saxon.] Signifies the whole machine of all the iron appurtenances of a bridle, as the bit-mouth, the branches, the curb, the sevil holes, the tranchefil, and the cross chains; but sometimes it is used to signify only the bit-mouth in particular. Farrier's Dict.

They light from their horses, pulling off their bits, that they might something refresh their mouths upon the grass. Sidney.

We have strict statutes, and most biting laws,
The needed bits and curbs of headstrong steeds. Shakesp. Measure for Measure.

He hath the bit fast between his teeth, and away he runs. Stillingfleet.

                Unus'd to the restraint
Of curbs and bits, and fleeter than the winds. Addis. Cato.