KHOI, a walled town of Persia, province of Azerbaijan, on a tributary of the Kar, 15 miles N. of Lake Urumiah. It is situate in a very fertile district, and is described as one of the best built towns in the Persian empire. The streets are wide and regular; and are shaded by rows of trees. Khoi carries on a considerable trade between Turkey and Persia. In the plain of Khoi, Shah Ismael signally defeated the Turks under Selim I., in 1514. Pop. about 15,000.