This realization expanded the geographical horizon of earlier European geographers, who had thought that the world only included Afro-Eurasian lands. Africa, Asia and Europe became collectively called the "Old World" of the Eastern Hemisphere, while the Americas were then referred to as "the fourth part of the world", or the "New World".[3]
Antarctica and Oceania are considered neither Old World nor New World lands, since they were only colonized by Europeans much later. They were associated instead with the Terra Australis that had been posited as a hypothetical southern continent.
^"America." The Oxford Companion to the English Language (ISBN0-19-214183-X). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. 33: "[16c: from the feminine of Americus, the Latinized first name of the explorer Amerigo Vespucci (1454–1512). The name America first appeared on a map in 1507 by the German cartographer Martin Waldseemüller, referring to the area now called Brazil]. Since the 16th century, the term "New World" has been used to describe the Western Hemisphere, often referred to as the Americas. Since the 18th century, it has come to represent the United States, which was initially colonial British America until it established independence following the American Revolutionary War. The second sense is now primary in English: ... However, the term is open to uncertainties: ..."