In times past, this term was used for what we now call Regent. It is considered sexist by some.
Basically the S/O of the Monarch was called the Consort, and put in charge of Arts & Sciences. Well in time it became apparent that it might be best to have this be based on actual Arts & Sciences skills. Plus, sometimes both monarch and consort might be of the same gender, which might make the term awkward.
Also used to refer to spouses or significant others of persons of high importance.