There is an old saying that “the Earth has six continents and seven seas.” In fact, that generalization is not too far off the mark. Earth has six continental landmasses:
Africa, South America, North America, Eurasia (Europe and Asia occupy a single large landmass), Australia,
and Antarctica. As for the seven seas, there are five great oceanic bodies of water and several smaller seas.
According to a 2017 paper published in the Geological Society of America’s journal, GSA Today, “The ‘Glossary of Geology’ defines a continent as ‘one of the Earth’s major landmasses, including both dry land and continental shelves.’ It is generally agreed that continents have all the following attributes: (1) high elevation relative to regions floored by oceanic crust; (2) a broad range of siliceous igneous, metamorphic and sedimentary rocks; (3) thicker crust and lower seismic velocity structure than oceanic crustal regions; and (4) well-defined limits around a large enough area to be considered a continent rather than a microcontinent or continental fragment… To our knowledge, the last point — how ‘major’ a piece of continental crust has to be to be called a continent — is almost never discussed.”
View More What Makes a Continent a Continent?