Also, Az·er·bai·dzhan. Formerly, Azerbaijan Soviet Socialist Republic.a republic in Transcaucasia, N of Iran and W of the Caspian Sea. 7,735,918; 33,430 sq. mi. (86,600 sq. km). Capital: Baku.
2.
a region of NW Iran, divided into two provinces in 1938: East Azerbaijan (4,114,084; Capital: Tabriz) and West Azerbaijan (1,971,677; Capital: Orumiyeh).