what is a group of many islands called
Noun. 1. archipelago-a group of many islands in a large body of water. island-a land mass (smaller than a continent) that is surrounded by water.rÂ·chiÂ·pelÂ·aÂ·go. n. pl. arÂ·chiÂ·pelÂ·aÂ·goes or arÂ·chiÂ·pelÂ·aÂ·gos. 1. A large group of islands: the Philippine archipelago. 2. A sea, such as the Aegean, containing a large number of scattered islands.