Continent

A very large contiguous landmass, often delimited by tectonic boundaries, which assist in distinguishing a small continent (such as Australia) from a large island, such as Greenland. Continental masses often extend a number of miles out into the ocean, only shallowly submerged; this region is known as the continental shelf.

The continents of Earth are Eurasia (often divided into Europe and Asia), Africa (occasionally included as a part of the Eurasian supercontinent which is then referred to as Eurafrasia, America (often divided into North America and South America), Antarctica and Australia.

Historically (hundreds of millions of years ago), a number of other continents and supercontinents have existed, such as Pangaea, Laurasia and Gondwanaland; these have been broken up and reassembled into the currently existing configuation, by the process of continental drift.