a former Trust Territory; an island group in the W Pacific Ocean, mandated to Japan after World War I and assigned to the US by the United Nations in 1947: comprised 2141 islands (96 inhabited) of the Caroline, Marshall, and Mariana groups (excluding Guam). In 1978 the Northern Marianas became a commonwealth in union with the US. The three remaining entities consisting of the Marshall Islands, the Republic of Palau (or Belau), and the Federated States of Micronesia became self-governing during the period 1979–80. In 1982 they signed agreements of free association with the US. Land area: about 1800 sq km (700 sq miles), scattered over about 7 500 000 sq km (3 000 000 sq miles) of ocean