island located in the western Indian Ocean off southeastern Africa and noted for its unique flora and fauna; formerly a French territory; became a republic of the French Community as theMal*a*gasy Republic\ˌma-lə-ˈga-sē\ in 1958; name changed to Madagascar in 1975; capital Antananarivo area 226,658 square miles (587,041 square kilometers), population 25,684,000