Harem means the women and the place where they live in a polygynous household. Most men are not allowed in there. The word harem comes from the Turkish word haram, meaning a sacred, forbidden place. Harems were meant for the royal upbringing of the future wives of noble and royal men. These women would be educated so that they were ready to appear in public as a royal wife.
In modern terms the word maybe used to describe a group of admiring women attracted to one man.