Probably related to Zinke (“point, prong”), from Old High German zint (“a jag, point”), from Proto-Germanic *tinduz, *tindaz (“prong, pinnacle”), from Proto-Indo-European *(e)dont- (“tooth, projection”).
Cognate with Dutch tinne (“battlement”), German Zinne (“pinnacle, battlement”), Danish tinde (“pinnacle, battlement”), Swedish tinne (“tooth of a rake”), Icelandic tindur (“spike, tooth of a rake or harrow, pinnacle, peak, battlement”).