1. noun /əˈmɛɹɪkən/
a) An inhabitant of the Americas. More often this is specified as either North American, Central American or South American.
Every Americans origin is, historically speaking, by immigration, if scientific speculation that points to a human origin in Asia and a migration to the New World over frozen Bering Strait turns out to be correct.
She went from Mexico to the USA before she gave birth, so her child would be an American.
2. adjective /əˈmɛɹɪkən/
Thanksgiving is an American tradition.
b) Of or pertaining to the Americas. More often this is specified as either "North American" or "South American."
He married an American woman in order to get an American passport.
Wikipedia foundation.