/ Dictionary / Index A Aegisthus: Meaning and Definition of Find definitions for: Ae•gis•thus Pronunciation: (ē-jis'thus), [key] — n. Class. Myth. a cousin of Agamemnon who seduced Clytemnestra, Agamemnon's wife, and was later killed by Orestes. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: aegisthus (Thesaurus) aegis Aegium Related Content Daily Word Quiz: nefarious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language