Rātch'et, n.

n. [Fr. rochet, It. rocchetto, a spindle, fr. rocca, a distaff; O. H. Ger. rocko, N. H. Ger. rocken, Icel. rockr, Eng. rock, rack. See ROCK.] A bar or piece of mechanism turning at one end upon a pivot, while the other end falls into the teeth of a wheel or rack, allowing the latter to move in one direction only; pawl; click; detent; — used for preventing backward motion in machinery, or for converting reciprocating into forward motion.

The term is also sometimes applied to the combination of wheel and pawl, as represented in the figure.

Ratchet-wheel. a, ratchet-wheel: b, reciprocating lever; c, small ratchet or pawl for