Taiwan (tī'wän') [key], Portuguese Formosa, officially Republic of China, island nation (2005 est. pop. 22,894,000), 13,885 sq mi (35,961 sq km), in the Pacific Ocean, separated from the mainland of S China by the 100-mi-wide (161-km) Taiwan Strait. Together with many nearby islets, including the Pescadores and the island groups of Quemoy and Matsu, it forms the seat of the Republic of China. The provisional capital is Taipei; Nanjing, on mainland China, is regarded as the official capital of the republic.
