Lewis & Short

Sĕsostris (lengthened Sĕsŏostris, Paul. Nol. ap. Aus. Ep. 19, 21), is, or Sĕsō-sis, ĭdis, m., = Σἐσωστρις, a celebrated king of Egypt, Luc. 10, 276.
Abl. Sesostre, Plin. 33, 3, 15, § 52.
Gen. Sesosidis, Plin. 36, 11, 15, § 74 (al. Sesothis) Sillig N. cr.
Abl. Sesoside, Tac. A. 6, 28 Orell. N. cr.