First Lady is an unofficial title used for the wife or hostess of a non-monarchical head of state or chief executive. The term is also used to describe a woman seen to be at the top of her profession or art. Collectively, the President of the United States and his spouse are known as the First Couple and, if they have a family, they are usually referred to as the First Family.

The First Lady of the United States (FLOTUS) is an unofficial title and position traditionally held by the wife of the president, concurrent with his term of office. Historically, if a president is not married, or if the president's wife is unable to act as First Lady, the president usually asks a female relative or friend to act as White House hostess.