ADIRBEITSAN, in Geography, a province of Persia, in Asia, and part of the ancient Media. It is bounded on the north by the province of Schirvan, on the south by Irac-Agemi and Curdisan, on the east by Ghilan and the Caspian sea, and on the west by Turcomania. E. Long. 42° to 48°. N. Lat. 36° to 39°.