bêšu - to depart, to move away, to part company, to fork, to produce a bifurcation
(CAD B 214, AHw. 123)
No definitive etymology can be suggested. Cf. perhaps JBA bḥš “to stir, to shake; to search” (DJBA 196), Syr. bḥaš “agitavit, movit, excitavit” (LSyr. 66), Mnd. bhš “to search, to examine” (MD 54). Alternatively, cf. Syr. bˁt (af.) “excitavit” (LSyr. 85), Arb. bˁṯ “to send; to raise, to excite, to put in motion or action” (Lane 222).