c. 1350–1400, Middle English clokke, clok, cloke, from Middle Dutch clocke ("bell, clock"), from Old Northern French cloque ("bell"), from Medieval Latin clocca, probably of Celtic origin, from Proto-Celtic *klokkos ("bell") (compare Welsh cloch, Old Irish cloc), either onomatopoeic or from Proto-Indo-European *klek- ("to laugh, cackle") (compare Proto-Germanic *hlahjaną ("to laugh")).
Related to Old English clucge, Saterland Frisian Klokke ("bell; clock"), Low German Klock ("bell, clock"), German Glocke, Swedish klocka.