An Etymological Dictionary of the German Language/Annotated/Glocke
Glocke, feminine, ‘bell, (public) clock,’ from the equivalent Middle High German glocke, Old High German glocka (never chloccha), feminine; corresponding to Dutch klok, Anglo-Saxon clugge, clucce, English clock, Old Icelandic klukka, feminine, ‘bell’; not originally a German word, since Old High German chlocchôn, ‘to knock,’ cannot well be allied. The Middle Latin clocca recorded in the 8th century, from which French cloche (in Italian campana) is derived, is probably due, like the Teutonic cognates, to Keltic origin; compare Welsh cloch, feminine, Old Irish cloc, masculine, ‘bell, clock,’ (primitively Keltic klukko). It is improbable that the Teutonic word is the source of the Romance and the Keltic terms, because Teutonic itself has usually borrowed the words relating to the Church and its institutions. The Old Keltic and Romance cognates in the form of klukka found their way into Teutonic; the High German forms (Swiss klokke, not χlokχe) may have been first adopted about 800 A.D., from Low German (Anglo-Saxon).