Sestiacus
Could not find Sestiacos in Logeion dictionaries.
Sestiacos Proper-name adjective: masculine accusative plural of Sestiacus
Sestĭăcus, a, um, v. Sestos, A.
Sēstiacus, a, um, s. Sēstos.
Sēstĭăcus, a, um, de Sestos : Stat. S. 1, 3, 27.