An island is a landmass (smaller than a continent) that is surrounded by water. Many island countries are spread over an archipelago, as is the case with Indonesia, Japan, and the Philippines—these countries consist of thousands of islands. Others consist of a single island, such as Barbados, Dominica, and Nauru; a main island and some smaller islands, such as Cuba, Iceland, and Sri Lanka; a part of an island, such as Brunei, the Dominican Republic, East Timor, and the Republic of Ireland; or one main island but also sharing borders in other islands, such as the United Kingdom (Great Britain and a part of Ireland).
The list also includes two states in free association with New Zealand, the Cook Islands and Niue, as well as two states with limited diplomatic recognition which have de facto control over territories entirely on the islands, Northern Cyprus and Taiwan. In total, 50 island countries have been included in the lists.