What is the time a king or queen is on the throne?

When a prince or princess who is first in line to the throne, they are called the Heir-Apparent. In example, HRH The Prince of Wales is the Heir-Apparent to the throne of England. When they ascend to the throne, they're called the Monarch. When a King marries a woman, she is not only called the queen, she is called the Heir Consort to the King, and likewise.