monarch
noun [ C ] uk/ˈmɒn.ək/ us/ˈmɑː.nɚk/
君王;国王，皇帝;女王，女皇
a king or queen
a hereditary monarch 世袭的国王
Britain's head of state is a constitutional monarch (= only has very limited powers). 英国的国家元首是君主立宪的国王或女王。
Synonyms: crowned head sovereign (RULER)
Compare: king noun (MALE RULER)queen (WOMAN)royal noun