Interregnum queen
Appearance
In Ancient Egyptian civilization, interregnum queen was a type of ruler of the kingdom. According to a 1932 report, she would have been the Great Royal Wife (ideally) of the previous pharaoh who was ruling as regent in place of her young son. Until her son reached the age to assume the role of pharaoh, he would have been the de jure pharaoh sharing power with his mother. In practice, the interregnum queen alone ruled until the pharaoh came of age.
The term may have been the equivalent of "Queen mother." Her role was that of a queen regent—requiring the leadership of a female monarch acting on behalf of the royal offspring.