Five continents

A continent is one of several very large landmasses on Earth. Generally identified by convention rather than any strict criteria, up to seven regions are commonly regarded as continents. Ordered from largest in size to smallest, they are: Asia, Africa, North America, South America, Antarctica, Europe, and Australia.

Geologically the continents largely correspond to areas of continental crust that are found on the continental plates. However some areas of continental crust are regions covered with water not usually included in the list of continents. The area referred to as Zealandia is one such area (see submerged continents below).

Islands are frequently grouped with a neighbouring continent to divide all the world's land into geopolitical regions. Under this scheme, most of the island countries and territories in the Pacific Ocean are grouped together with the continent of Australia to form a geopolitical region called Oceania.

By convention, "continents are understood to be large, continuous, discrete masses of land, ideally separated by expanses of water." Several of the seven conventionally recognized continents are not discrete landmasses separated completely by water. The criterion "large" leads to arbitrary classification: Greenland, with a surface area of 2,166,086 square kilometres (836,330 sq mi) is considered the world's largest island, while Australia, at 7,617,930 square kilometres (2,941,300 sq mi) is deemed the smallest continent.

Earth's major landmasses all have coasts on a single, continuous World Ocean, which is divided into a number of principal oceanic components by the continents and various geographic criteria.

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