Noun
a female sovereign ruler
Source: WordNetIsabella was said to resemble her father, and not her mother, queen regnant of Navarre, a plump, plain woman. Source: Internet
While most monarchs have been male, many female monarchs also have reigned in history; the term queen regnant refers to a ruling monarch, while a queen consort refers to the wife of a reigning king. Source: Internet
She continued to regard herself as queen regnant all her life. Source: Internet
The strained spousal relations paralleled a factional struggle at the royal court in which Tamar was becoming more and more assertive of her rights as a queen regnant. Source: Internet