An Etymological Dictionary of the German Language/Annotated/Zacken
Zacken, masculine, ‘point, peak, prong, tooth (of a comb),’ from the equivalent Middle High German (Middle German) zacke, masculine and feminine; properly a Middle German and Low German word. Compare Dutch tak, masculine, ‘twig, branch, point,’ North Frisian tâk, ‘point,’ to which Old Icelandic tág, masculine, ‘willow twig,’ English tack, are also probably allied. The latter are perhaps primitively cognate with Sanscrit daçâ, ‘fringe,’ or with Greek δοκός, ‘beam’ (Teutonic takko-, Aryan dokno-?). It is uncertain whether Zinke is allied.