A continent is a large landmass on a planet or moon. On Earth, seven areas are generally regarded in reference books as continents: North America, South America, Europe, Asia, Africa, Oceania, and Antarctica. The definition can include the landmass and its nearby islands (thus for example, Oceania—formerly called Australasia—consists of more than just Australia). The definition is a conventional one, as continents may share the same landmass: Europe and Asia are separated not by water but by the Ural mountains; together they are sometimes termed Eurasia and regarded as a sngle continent. Geographers generally do not take the concept of a continent very seriously, considering it has little scientific value.
Continents exist for geological reasons. Their crusts are much thicker and lighter than those of oceans, so that they correspond to emerged land. From the point of view of geology, and more precisely in the theory of plate tectonics, there are more continents than in geography. In plate tectonics, for example, Arabia constitutes a separate plate, partially constituted by continental crust.
The concept was first introduced in the early 17th century. Since then a variety of lists of continents have been used. In one, still in use in the early 19th century, there were considered to be only two continents, the Old and the New, also called the Old and New Worlds. Australia was added in the late 19th century. In the 20th century, Antarctica was added.
Among the general public (as seen for example on the internet), a 5-continent scheme is much more widely known than the 7-continent one found in reference books now:
- America or the Americas
- Australasia, Australia or Oceania
This is used officially by, for example, the United Nations and the International Olympic Committee (as symbolized by the five rings of its logo).
Grouping of countries into continents
Central America and the Caribbean island nations are included in North America. Most of the scattered island nations of the Pacific are included in the continent variously called Australasia, Australia or Oceania.
Countries disputed between continents
The UN includes Armenia, Azerbaijan, Cyprus, Georgia, Israel and Turkey in Asia, while the IOC includes them in Europe.
Countries divided between continents
The UN and IOC count each country as belonging to just one continent.
The World Gazetteer recognizes six countries as divided between continents: Egypt, Indonesia, Russia, Spain, Turkey and the USA. In addition, the BBC recognizes France as partly outside Europe.
- See Webster's dictionary.