A citizen of the United States is an American. United States, American and U.S. refer to the country adjectivally (American values, U.S. forces). American rarely refers to subjects not connected with the United States.
Costume Department | Actress. Anna Wintour was born in Hampstead, London, England, the daughter of an American mother, Eleanor Trego (Baker), and an English father, Charles Wintour, former Editor of the Evening Standard. She is from an upper-class family, with many prominent ancestors.
Anna Wintour realises that her shoes, as she sits with her legs crossed in the front row, will appear in almost every catwalk photo for the rest of eternity, and, perhaps, can't be bothered to choose a fresh design for every appearance, to be picked over by people like me.