“Aegis: (fr Gr, aix, ‘goat’) Variously interpreted as a shield made of goatskin or as the awesome thundercloud of Zeus. Homer depicts the aegis as an impregnable shield made by the god Hephaestus. On occasion Zeus lent the aegis to other gods; particularly Athene and Apollo. The aegis symbolized the gods’ special powers. Hence the term has come denote authority and protection.”
Excerpted from: Murphy, Bruce, ed. Benet’s Reader’s Encyclopedia, Fourth Edition. New York: Harper Collins, 1996.