Turoyo

ḳəm, ḳum - vor, hinter (in front of, behind) (RW 421)

PS
*ḳVdm - in front of, before (Arakelova 2001:46, Kogan 2015:395)
The preposition is considered to be derived from the verbal root *ḳdm ‘to be in front, to precede’