Cleft, n. [OE. clift; cf. Sw. klyft cave, den, Icel. kluft cleft, Dan. klöft, G. kluft. See Cleave to split and cf. 2d Clift, 1st Clough.] 1. A space or opening made by splitting; a crack; a crevice; as, the cleft of a rock. Is. ii. 21.
2. A piece made by splitting; as, a cleft of wood.
3. (Far.) A disease in horses; a crack on the band of the pastern.
Branchial clefts. See under Branchial.
Syn. — Crack; crevice; fissure; chink; cranny.