The Sem. terms listed below are commonly thought to be borrowed from an IE satəm-language, v. Gamkrelidze-Ivanov 1984 560, 914 (PIE *ek[h]wo- ‘horse’) and Tropper 2000 45 (with a special emphasis on Luvian azzuwa-). Within the framework of this hypothesis (quite promising as such), one should not disregard some difficulties as far as the word-structure of the Semitic terms is concerned: both the loss of the word-initial vowel and the reduplication are present already in the earliest Sem. attestations.
The Akkadian word together with Ugr. ssw, s̀s̀w , Hbr. sūs and Syr. sūsyā are all related to each other, but the common source is usually thought to be foreign rather than Semitic
Var. s̀s̀w. Cf. sswt ‘mare’. Of uncertain origin (cf. SED II No. 199), but, contra Watson 2007: 70, certainly not an Akkadism in Ugaritic (Kogan 2015: 359).
Quoted as an Egyptian dialectal word (cf. BH 445), not attested in the available dictionaries of Classical Arabic. Arb. sws ‘to rule over people’ (BK 1 1164, LA VI 108) is often regarded as derived from the present root with a meaning shift from ‘to drive horses’ (e.g., Hommel 1879 45-6, 54); cf. especially Arb. Syr. sā́yes ‘take care of or heal a horse’ (Barthélemy 373)