concubine

noun

1. A sexual partner, especially a woman, to whom one is not or cannot be married.
2. A woman who lives with a man, but who is not a wife.

   “And that is more than I will yield unto: / I know I am too mean to be your queen, / And yet too good to be your concubine.”

3. (historical)A slave-girl or woman, kept for instance in a harem, who is held for sexual service.

   “He ſhall be made a chaſte and luſtleſſe Eunuch, And in my Sarell tend my Concubines:”

   “And the Levite, the husband of the woman that was slain, answered and said, I came into Gibeah that belongeth to Benjamin, I and my concubine, to lodge. And the men of Gibeah rose against me, and beset the house round about upon me by night, and thought to have slain me: and my concubine have they forced, that she is dead. And I took my concubine, and cut her in pieces, and sent her throughout all the country of the inheritance of Israel: for they have committed lewdness and folly in Israel.”

   “Solomon, who was one of the Deity's favorities, had a copulation cabinet composed of seven hundred wives and three hundred concubines.”