the Americasといえば、南北アメリカの総称です。当然、中米も含まれるでしょう。
The Americas comprise the totality of the continents of North and South America. (Wikipedia)
【訳】The Americasとは、北アメリカと南アメリカの両大陸全体のこと。
Peopling the Americas
ちなみにpeopleというのは動詞の場合の意味は、To live, stay or work in a particular place（引用元：macmillandictionary.com）（ある地域に人が住む）という意味です。
The prehistory of the Americas (North, South, and Central America, and the Caribbean) begins with people migrating to these areas from Asia during the height of an Ice Age. (Wikipedia)
History books state that the Americas were discovered in 1492 when Christopher Columbus stumbled across a group of islands whilst searching for a route to India – this is why the island group he first landed upon is now called the West Indies. It is fair to say, that using the term “discovered” does cause some confusion, as parts of the Americas were as densely populated and as civilised as Europe – and had been for thousands of years. However, Columbus’ discovery of the Americas took place in a time when European monarchs were casting their naval fleets across the seas to “discover” new lands and trade routes to claim their own. （The Discovery of the Americas)
