Royal Consort
Queen, Princess, Empress
noun
The kanji and the vocabulary are exactly the same, so this means royal consort. Depending on who she's married to, she could be a queen, a princess, or even an empress.
妃 can overlap in meaning with 后, but 后 is reserved for the highest-ranking consort, like an empress or queen, while 妃 is a more general word which includes lower-ranking consorts and the wives of other royal family members. In modern Japanese, the kana version きさき often appears in fairytale-style stories with kings and queens. But it's good to know both kanji, especially if you're reading anything historical.
How do you know someone is a royal consort? Because they kiss a king (きさき). If you kiss a king, maybe you can be a royal consort too!
帝が新しい妃を迎えるという噂が広まっていた。
Rumors were spreading that the emperor would take a new consort.
彼女は国王の妃として人々に敬愛されていました。
She was loved by the people as the king's consort.
お妃様は静かに本を読みながら午後をお過ごしになられました。
Her Majesty spent the afternoon quietly reading a book.