ACHAEMENID

[Achae.me.nid] n, pl -menids also -men.i.dae [Gk Achaimenides, fr. Achaimenes, 7th cent. b.c. Pers. king, founder of the dynasty + -ides (patronymic suffix)] (1889): a member of the ruling house of ancient Persia generally considered historically important from the assumption of power by Cyrus the Great (559 b.c.) to the overthrow of Darius III (330 b.c.)