Akkadian

sīsû - horse (CAD S 328, AHw. 1051)

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

Areal reconstruction
*sVwsVw- - horse (SED No. 199)
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.