Aydin (Īdŭnˈ) [key], city (1990 pop. 106,603), capital of Aydin prov., W Turkey, on the Büyük Menderes River. It is the trade center for a farm region where olives, figs, cotton, and tobacco are grown. The city was destroyed by fire in 1922 and has been completely rebuilt. Nearby are the ruins of the ancient Greek city of Tralles.