What is the meaning of Mistress?

A woman, specifically one with great control, authority or ownership.

A female teacher.

The other woman in an extramarital relationship, generally including sexual relations.

A dominatrix.

A woman well skilled in anything, or having the mastery over it.

a woman regarded with love and devotion; a sweetheart.

A married woman; a wife.

The jack in the game of bowls.

A female companion to a master (a man with control, authority or ownership).

female equivalent of master

female equivalent of mister

Of a woman: to master; to learn or develop to a high degree of proficiency.

To act or take the role of a mistress.

Source: wiktionary.org