Paraphrasing from Wikipedia, the definition of Femdom is this:
Femdom: Female dominance (or femdom) refers to BDSM relationships and BDSM scenes in which the dominant partner is female. A dominant woman, she may be called a Domme, Femdomme, Domina, or Dominatrix, depending on context or personal preference. A female dominant in a master/slave relationship is often termed a Mistress, not to be confused with the colloquial usage of mistress as a kept sexual partner without a similarly formalized power relationship. (Just in case you had any confusion or stopped by this site by mistake...but I seriously doubt that.)
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