Sine 2015 An island is any piece of sub-continental land that is surrounded by water. Very small islands such as emergent land features on atolls can be called islets, skerries, cays or keys. An island in a river or a lake island may be called an eyot or ait, or a holm. A grouping of geographically or geologically related islands is called an archipelago, e.g. the Philippines.