The Americas was the collective name for North, Central, and South America. While North and South America were often considered distinct continents, the Americas were sometimes also counted as a single continent, the American continent.
In 2374, "Catarina" (Kathryn Janeway) was asked by a hologram of Leonardo da Vinci how she came to the Americas. She answered, "Oh, it's a long story. A Portuguese ship, some Turkish pirates, a couple of hurricanes", promising to fill him in later. (VOY: "Concerning Flight")