A queen regnant (plural: queens regnant) is a female monarch, equivalent in rank and title to a king, who reigns in her own right over a realm known as a "kingdom"; as opposed to a queen consort, who is the wife of a reigning king; or a queen regent, who is the guardian of a child monarch and rules temporarily in the child's stead, be it in sharing power, or in ruling alone. A princess regnant is a female monarch who reigns in her own right over a "principality"; an empress regnant is a female monarch who reigns in her own right over an "empire".