(Σθένιος), i.e. "the powerful," or " the strengthening," a surname of Zens, under which he had an altar in a rock near Hermione, where Aegeus concealed his sword and his shoes, which were found there by Theseus after he had lifted up the rock. (Paus. 2.32.7, 34.6.) One of the horses of Poseidon also bore the Sthenius. (Schol. ad Hom. Il. 13.23.)
[L.S]A Dictionary of Greek and Roman biography and mythology
Smith, William
A Dictionary of Greek and Roman biography and mythology. William Smith, LLD, ed. 1890