Ὑδάσπης: ου ὁ Гидасп (сев. приток Инда в Пенджабе) Plut.
Perhaps YAv. hu-δāta, well-made, well-formed + APers. aspa (comp.), horse, Av. aspa, Skt. açva; having well-formed horses; cf. Justi, NB. 131.