2. A mechanism composed of a ratchet wheel, or ratch, and pawl. See Ratchet wheel, below, and 2d Ratch. Ratchet brace, a circular wheel having teeth, usually angular, with which a reciprocating pawl engages to turn the wheel forward, or a stationary pawl to hold it from turning backward.
Origin: Properly a diminutive from the same word as rack: cf. F. Rochet. See Ratch, Rack the instrument.