An island or isle is any piece of land that is surrounded by water. Very small islands such as emergent land features on atollsare called islets. A key or cay is another name for a small island or islet. An island in a river or lake may be called an eyot. A grouping of geographically or geologically related islands is called an archipelago.
An island may still be described as such despite the presence of a land bridge, for example Singapore and its causeway, or the various Dutch delta islands, such as IJsselmonde. Some places may even retain â€œislandâ€ in their names for historical reasons after being connected to a larger landmass by a wide land bridge, such as Coney Island.
There are two main types of islands: continental islands and oceanic islands. There are also artificial islands. There is no standard of size which distinguishes islands from islets and continents.
The word island comes from Old English igland (from â€˜igâ€™, similarly meaning â€˜islandâ€™ when used independently, and -land carrying its contemporary meaning). However, the spelling of the word was modified in the 15th century by association with the etymologically unrelated Old French loanword isle, which itself comes from the latin word insula. Old English â€˜igâ€™ is actually a cognate of Latin aqua(water).
Continental islands are bodies of land that lie on the continental shelf of a continent. Examples include Greenland and Sable Island off North America;Barbados and Trinidad off South America; Great Britain, Ireland and Sicily offEurope; Sumatra, Borneo and Java off Asia; and New Guinea, Tasmania and Kangaroo Island off Australia.
A special type of continental island is the microcontinental island, which results when a continent is rifted. Examples are Madagascar and Socotra offAfrica; New Zealand; the Kerguelen Islands; and some of the Seychelles.
Another subtype is an island or bar formed by deposition of tiny rocks where a water current loses some of its carrying capacity. An example is barrier islands, which are accumulations of sand deposited by sea currents on the continental shelf. Another example is islands in river deltas or in large rivers. While some are transitory and may disappear if the volume or speed of the current changes, others are stable and long-lived. Islets are very small islands.