An Etymological Dictionary of the German Language/Zitze
Zitze, f., ‘nipple, teat,’ from the equiv. late MidHG. (rare) zitze, f.; comp. the corresponding LG. titte, f., Du. tet, f., AS. tit, m. (plur. tittas), E. teat, Swiss tisse, ‘teat.’ The usual word for ‘teat’ in OHG. is tutta, tuta, f., tutto, tuto, m.; MidHG. tutte, tute, f., tütal, n.; comp. Tüttel. In Romance occur the cognate words — Ital. tetta, zizza, zezzolo, ‘teat,’ Fr. tette, f., teton, tetin, m., ‘nipple,’ Span. teta, as well as Ital. tettare, Span. tetar, Fr. teter, ‘to suck’; the double forms with t and z imply that these words were borrowed from Teut.