First Lady

First Lady is an unofficial title used for the wife of a non-monarchical head of state or chief executive. 
Some countries have a title, official or unofficial, 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.
First Gentleman is used where the head of state's spouse has been a man, such as the Philippines or Malta. 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 governor.
First Spouse, a rare version of the title, can be used in either case where the spouse of a head of state is male or female. This term is used to promote gender equality and gender neutrality.