# Formosa former Portuguese name of Taiwan, an island in the Pacific Ocean near the mainland of southern China. The island was settled by the Portuguese in the 16th century. Japan had control of the island from 1895 until 1945. In 1949, communists took over the government of mainland China, and the nationalists, who had been in control of China, moved their seat of government to Taiwan and became known as the Republic of China. The United States supported and aided this government.