Cliff \Cliff\ (kl[i^]f), n. [AS. clif, cloef; akin to OS. klif, D. klif, klip, Icel. klif, Dan. & G. klippe, Sw. klippa; perh. orig. a climbing place. See {Climb}.] A high, steep rock; a precipice. {Cliff swallow} (Zo["o]l.), a North American swallow ({Petrochelidon lunifrons}), which builds its nest against cliffs; the {eaves swallow}.