Domme noun: a woman who enjoys, possibly prefers a position of authority in her erotic relationships. These relationships may or not involve sexual contact. The range can be from taking control to treating another person as owned property.
A Domme might be distinguished from a dominatrix. Dominatrix often implies that the woman is a professional sex worker, sometimes denoted as a ProDomme. Dominatrix also has a common, vulgar usage to describe any assertive female.