Gr. Myth. son of Agamemnon and Clytemnestra, who, with the aid of his sister Electra, avenges the murder of his father by killing his mother and her lover Aegisthus
Origin:
L < Gr Orestēs < oros, mountain: see orient
See Orestes in American Heritage Dictionary 4
noun Greek Mythology
The son of Agamemnon and Clytemnestra, who with his sister Electra avenged the murder of his father by murdering his mother and her lover Aegisthus.