► king a man who is the leader of a country because he is from a royal family: King George VI was the country’s ruler at the time.
► queen the female ruler of a country, or the wife of a king: She became queen in her twenties when her father died.
► prince the son of a king or queen, or the male ruler of some small countries: Prince Charles will become king when his mother dies.
► princess the daughter of a king or queen, or the wife of a prince: Both princesses married into other royal families.
► monarch a king or queen: The current British monarch has reigned for over 60 years.
► ruler someone such as a king, who has official power over a country and its people: Gradually his power increased until he was the ruler of a large part of Spain.
► emperor the ruler of an empire (=group of countries): He was killed not long after he became emperor of the Roman Empire.
► sovereign formal a king or queen: The country was attacked while its sovereign was abroad.