‖n. [ L. aegis, fr. Gr. a'igi`s a goat skin, a shield, a'i`x goat, or fr. 'ai`:ssw to rush. ] A shield or protective armor; -- applied in mythology to the shield of Jupiter which he gave to Minerva. Also fig.: A shield; a protection. [ 1913 Webster ]
(n) (Greek mythology) the seducer of Clytemnestra and murderer of Agamemnon who usurped the throne of Mycenae until Agamemnon's son Orestes returned home and killed him