Proto-West-Caucasian: *rǝχʷǝ (~t-, d-)
Meaning: 1 butter (melted) 2 fat
Adyghe: tχʷǝ 1
Kabardian: tχʷǝ 1
Ubykh: tχʷǝ 2
Comments: PAK *tχʷǝ. Ub. tχʷǝ is hardly a loan from AK because of semantic difference. Despite Abdokov 1973, 68 and Shagirov 1,78 PAT *xʷǝ-ša 'melted butter' can not be related (the correspondence PAT *xʷ : PAK *χʷ does not exist).
Judging from PAK t- and Ub. t- in Anlaut *r-, *t- or *d- can be reconstructed; *r- is most probable because of external correspondences.
