'Concubines' in the Bible

And David took him more concubines and wives out of Jerusalem, after he had come from Hebron; and there were yet sons and daughters born to David.

And the king went forth, and all his household after him, and the king left ten women, concubines, to keep the house.

And Ahithophel said to Absalom, Go in to thy father's concubines, whom he has left to keep the house; and all Israel shall hear that thou art become odious with thy father; and the hands of all that are with thee shall be strong.

So they spread a tent for Absalom upon the roof; and Absalom went in to his father's concubines in the sight of all Israel.

And Joab came into the house to the king, and said, Thou hast put to shame this day the faces of all thy servants who have this day saved thy life, and the lives of thy sons and of thy daughters, and the lives of thy wives and the lives of thy concubines;

And David came to his house at Jerusalem; and the king took the ten women, concubines, whom he had left to keep the house, and put them in a house of confinement and maintained them, but did not go in to them. So they were shut up unto the day of their death, living in widowhood.