↑McArthur 1992:33: "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 16c, a name of the western hemisphere, often in the plural Americas."
↑"Western Hemisphere," Merriam-Webster's Geographical Dictionary, ed. 3a (Springfield Massachusettae: Merriam-Webster, 2001), 1294: "The part of the Earth comprising North and South America and surrounding waters; longitudes 20°W and 160°E are often considered its boundaries."