Concubine (noun)

1. A woman who lives with a man and has a sexual relationship with him but is not his wife, typically in a long-term relationship.
2. A secondary wife or mistress.

Origin:

From the latin concubina, meaning a woman who lives with a man without being married to him, from con- (together) + cubare (to lie).

Examples:

1. In ancient China, wealthy men often had multiple concubines.
2. The king had many concubines but only one queen.
3. She was the king's favorite concubine.
4. The emperor's concubines lived in separate quarters in the palace.
5. The wealthy man had a number of concubines but no legal wife.