PS

*ka/iska/is-, *kVsˀw- - back, side or front part of body (of a sheep?) (SED No. 152)

A difficult case: meanings and stem patterns differ greatly.

Akkadian
kaskasu - soft part of the sheep's breast-bone; a cut of the meat of a sheep (CAD k 244, AHw 454)
Arabic
kusˀ-, kusy- - rear, last part, backside, behind, behind of the head (BK 2 894, WKAS I 168)
Tigre
kəšwät - sheep's side (WTS 408)
Amharic
kiskissa - bone at the base of the tail (AED 1410)