(Ἀτρείδης), a patronymic from Atreus, to designate his sons and descendants. When used in the singular, it commonly designates Agamemnon, but in the plural it signifies the two brothers, Agamemnon and Menelaus. (Hom. Il. 1.12, &c.; Hor. Carm. 2.4.7, &c.)