The Collaborative International Dictionary of English v.0.48:
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. [1913 Webster] Cliff swallow (Zool.), a North American swallow (Petrochelidon lunifrons), which builds its nest against cliffs; the eaves swallow. [1913 Webster]