A harem was a collection of females kept by an individual for their own pleasure.
Kor and Curzon Dax once broke into a harem on Renavi that belonged to a Duke. (DS9: "Once More Unto the Breach")
Doctor Chaotica had a harem full of slave girls that would be freed in chapter 18 of The Adventures of Captain Proton. (VOY: "Bride of Chaotica!")