queen consort; empress consort
Refers specifically to the wife of a reigning king or emperor, not a reigning monarch herself. For a reigning queen, 女王 (じょおう) is used.
The queen consort was loved by the people.
The British queen consort is busy with official duties.
She became queen consort through marriage.
The king took a princess from a neighboring country as his queen consort.
王妃 is the general term for a queen or princess consort in any monarchy, while 皇太子妃 specifically denotes the wife of a crown prince in an imperial system.
女王 is a reigning queen who holds the throne herself, while 王妃 is merely the wife of a reigning king and has no ruling power of her own.
Compound of 王 (おう, 'king') and 妃 (ひ, 'princess' or 'consort'). The term has been used historically to denote the wife of a monarch.