First Lady

First Lady is an unofficial title used for the wife of a non-monarchical head of state or chief executive.First Lady, Merriam-Webster Dictionary, retrieved 2014-12-30First Lady, Oxford Dictionaries , retrieved 2014-12-30Amanda Foreman, "Our First Ladies and Their Predecessors", Wall Street Journal, May 30–31, 2015, C11, https://www.wsj.com/articles/the-first-ladies-and-their-predecessors-1432830990, retrieved 2015-5-30 

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.

References