A chain of coral and volcanic islands in Micronesia (including Guam and the Northern Marianas) halfway between New Guinea and Japan; discovered by Magellan in 1521 WordNet 3.0 & Open English WordNet

The Mariana Islands, also simply the Marianas, are a crescent-shaped archipelago comprising the summits of fourteen longitudinally oriented, mostly dormant volcanic mountains in the northwestern Pacific Ocean, between the 12th and 21st parallels north and along the 145th meridian east. Wikipedia

A group of islands in the north-western Pacific Ocean Wikipedia Disambiguation

Archipelago in western North Pacific Ocean Wikidata

An archipelago in the western Pacific Ocean, a part of the geographical Micronesia. Wiktionary

Archipelago in Micronesia. Wiktionary (translation)