Island
An island or isle 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, and a small island off the coast may be called a holm. A grouping of geographically or geologically related islands is called an archipelago, such as the Philippines.
Islet
As suggested by its origin as "islette", an Old French diminutive of "isle", use of the term implies small size, but little attention is given to drawing an upper limit on its applicability.
Whether an islet is considered a rock or not can have significant economic consequences under Article 121 of the UN Convention on the Law of the Sea, which stipulates that "Rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf." One long-term dispute over the status of such an islet was that of Snake Island (Black Sea).