Orestes

[aw-res-teez, oh-res‐] /ɔˈrɛs tiz, oʊˈrɛs‐/
noun
1.
Classical Mythology. the son of Agamemnon and Clytemnestra, and the brother of Electra and Iphigenia: he avenged the murder of Agamemnon by killing Clytemenestra and her lover, Aegisthus, then was pursued by the Furies until saved by Athena.
2.
(italics) a tragedy (408 b.c.) by Euripides.
British Dictionary definitions for Orestes

Orestes

/ɒˈrɛstiːz/
noun
1.
(Greek myth) the son of Agamemnon and Clytemnestra, who killed his mother and her lover Aegisthus in revenge for their murder of his father
Word Origin and History for Orestes

son of Agamemnon and Clytaemnestra, from Greek Orestes, literally "mountaineer," from oros "mountain" (see oread).

Orestes in Culture
Orestes [(aw-res-teez)]

In classical mythology, the son of Agamemnon and Clytemnestra, and brother of Electra. Agamemnon was killed by Clytemnestra and her lover, Aegisthus. To avenge the murder, Orestes and Electra killed them both.