- an island, belonging to the United States, in the northern Pacific, east of the Philippines: the largest of the Marianas group; U.S. naval station. 206 sq. mi. (535 sq. km). Capital: Agaña. Abbreviation: GU (for use with zip code).
- an island in the N Pacific, the largest and southernmost of the Marianas: belonged to Spain from the 17th century until 1898, when it was ceded to the US; site of naval and air force bases. Capital: Agana (now officially spelt Hagåtña). Pop: 160 378 (2013 est). Area: 541 sq km (209 sq miles)
