Zanzibar (/ˈzænzɨbɑr/; from Arabic: زنجبار Zanjibār, from Persian: زنگبار Zangibār "Coast of Blacks"; zangi [black-skinned] + bār [coast]) is a semi-autonomous part of Tanzania, in East Africa. It is composed of the Zanzibar Archipelago in the Indian Ocean, 25–50 kilometres (16–31 mi) off the coast of the mainland, and consists of numerous small islands and two large ones: Unguja (the main island, referred to informally as Zanzibar), and Pemba.