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 children, they are usually referred to as the First Family.
The term is sometimes used, primarily in the U.S., to refer to the spouse of other non-monarchical heads of state, even though they do not have that style in their own country. Some other countries have a title, formal or informal, that is or can be translated as first lady. The title is not normally used for the wife of a head of government who is not also head of state.
The term in the United States is also used to refer to wives of governors and, less formally, to wives of college and university presidents. It has even been used in reference to female spouses of men who were chairmen of major corporations. While there has never been a male spouse of a U.S. President, "First Gentleman" is used in the United States for the husband of a state governor.
The designation First Lady seems to have originated in the United States, where one of the earliest uses in print, in 1838, was in reference to Martha Washington. Other sources indicate that, in 1849, President Zachary Taylor called Dolley Madison "first lady" at her state funeral, while reciting a eulogy written by himself; but no copy of that eulogy has been found. The term might have roots as far back as the end of the Roman Republic. When Gaius Octavius became Emperor he did not want to assume the titles rex (king) or dictator since it could create resentment amongst senators and other influential men. He thus took the more humble title Princeps Civitatis, or the first citizen, which made his wife Principa Femina, the first lady.