The Avestan word zānu-
Word zānu-
Meaning knee
See also Homeric Greek: γόνυ ‘knee’
Proto-Indo-European: *ĝonu ‘knee’
Hittite: ge-e-nu ‘knee’
Tocharian B: keni ‘knee’

Other words that might be of interest
zānu- ‘jaw’, čarǝman- ‘skin’, zǝrǝd- ‘heart’, sarah- ‘head’, gava ‘hand’, hizū ‘tongue’, staman ‘mouth’, bruuat̰ ‘eyebrow’, ast- ‘bone’, tanū- ‘body’, bāzu ‘arm, leg’, nāfa- ‘navel’, xvafəna- ‘sleep’, pad- ‘foot’