A queen regnant (plural "queens regnant") is a female
monarch possessing and exercising all of the monarchal powers of a king, in contrast with a
queen 'consort', who is the wife of a reigning
king, and in and of herself has no official powers of state.Technically, a king may also be a "king regnant" or a "
king consort" — but this distinction is unusual and, for example, has been used only twice in the history of the British and its predecessor monarchies. In all current monarchies that allow for a queen regnant to take the Throne, the husband of such a queen is not titled king, generally ranking as a prince. The husband of
Mary I of England and Ireland and the second husband of
Mary I, Queen of Scots were both created kings consort of their wives' realms, but they were not liked, and the marriages were short. The husband of
Mary II, Queen of England and Ireland, and Queen of Scots, was named king regnant co-sovereign with her, as
William III of England, II of Scots, and I of Ireland — but this was the only occasion of co-sovereignty, at least officially. Thereafter, the husbands of queens regnant in Britain have been informally styled princes consort (the formal title "Prince Consort," however, having only been granted to
Prince Albert, the husband of
Queen Victoria).
See more at Wikipedia.org...