Overview
The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas. The term gained prominence in the early 16th century during Europe's Age of Discovery, after Italian explorer Amerigo Vespucci published the Latin-language pamphlet Mundus Novus, presenting his conclusion that these lands (soon called Americas based on Amerigo's name) constitute a new continent. 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 thus 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".
Australia and Antarctica are considered neither Old World nor New World lands, since they were only discovered by Europeans much later. They were associated instead with the Terra Australis that had been posited as a hypothetical southern continent.
Origin of term
The Florentine explorer Amerigo Vespucci is usually credited for coming up with the term "New World" (Mundus Novus) for the Americas in his 1503 letter, giving it its popular cachet, although similar terms had nonetheless been used and applied before him.
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