Main Entry: America
Usage: geographical name
1 either continent (N. America or S. America) of the western hemisphere
2 or the Americas
/-k&z/ the lands of the western hemisphere including N., Central, & S. America & the W. Indies
3 UNITED STATES OF AMERICA
I suspect they got this from an American dictionary.
Think about it...
This the same country that arbitrarily redefines words in 'easier to spell' variations such as aluminium/aluminum, aeroplane/airplane, colour/color, night/nite (OK 'nite' is not ubiquitous in the USA.)
This is from the same country where the RIAA can redefine the meaning of a word in the dictionary for its own purposes.
The New Lexicon Webster's Encyclopaedia Dictionary of the English Language (Canadian Edition of an American Dictionary):
America: the two continents North America and South America, extending from beyond the Arctic Circle to the subantarctic regions and joined by a central isthmus. North America is centred on longitude 100 deg W while South America lies further East centred on longitude 60 deg W. The name is from Americus Vespucius (Amerigo Vespucci). The total land area is over 16,000,000 sq. miles and the estimated total pop. 500,000,000 Linguistically and culturally the Americans are known as Anglo-America (the U.S.A. and Canada) and Latin America (Mexico, Central America, most of the West Indies, and South America)
So essentially, the American dictionary makers are saying that outside of the USA, America != United States of America.