An Etymological Dictionary of the German Language/Annotated/Kitze
Kitze (1.), feminine, from the equivalent Middle High German kitze, kiz, neuter, Old High German chizzî, kizzîn, neuter, ‘kid’; from Teutonic *kittîn, neuter, with the original diminutive suffix -îna, which appears in Küchelein and Schwein. Gothic *kidi (kidjis), neuter, may be deduced from Old Icelandic kið, neuter, ‘she-goat,’ whence English kid is borrowed (an English word cognate with Scandinavian must have had an initial ch). Further, the assumed Gothic *kidi and *kittein, with medial dentals, are related to each other, just as the forms assumed under Ziege, tigô and tikkein, with medial gutturals. The close correspondence between Kitze and Zicke proves that they are related; both are pet names for Geiß, ‘goat’ (compare Swiss gitzi for Old High German chitzî).
Kitze (2.), Kietze, feminine, ‘kitten, kid, fawn,’ not found in Middle High German and Old High German, but probably existing in the vernacular, as is indicated by the specifically High German tz compared with Low German tt (kitte); compare Middle English chitte, ‘kitten,’ from an unrecorded Anglo-Saxon *citten (English kitten); Middle English kitlung, English kitling, are probably borrowed from Scandinavian ketlingr, ‘kitten.’ The cognates are related by gradation to Katze.