1. A woman who has a continuing sexual relationship with a usually married man who is not her husband and from whom she generally receives material support.
2. A woman in a position of authority, control, or ownership, as the head of a household: Thirteen years had seen her mistress of Kellynch Hall (Jane Austen).
a. A woman who owns or keeps an animal: a cat sitting in its mistresss lap.
b. A woman who owns a slave.
4. A woman with ultimate control over something: the mistress of her own mind.
a. A nation or country that has supremacy over others: Great Britain, once the mistress of the seas.
b. Something personified as female that directs or reigns: my mistress . . . the open road (Robert Louis Stevenson).
6. A woman who has mastered a skill or branch of learning: a mistress of the culinary art.
7. Mistress Used formerly as a courtesy title when speaking to or of a woman.
8. Chiefly British A woman schoolteacher.
[Middle English maistresse, from Old French, feminine of maistre, master, from Latin magister; see master.]
Usage Note: English has no shortage of terms for women whose behavior is viewed as licentious, but it is difficult to come up with a list of comparable terms used of men. One researcher, Julia Penelope, stopped counting after she reached 220 such labels for women, both current and historical, but managed to locate only 20 names for promiscuous men. Murial R. Schultz found more than 500 slang terms for prostitute but could find just 65 for the male terms whoremonger and pimp. A further imbalance appears in the connotations of many of these terms. While the terms generally applying only to women, like tramp and slut, are almost always strongly negative, corresponding terms used for men, such as stud and Casanova, often carry positive associations. · Curiously, many of the negative terms used for women derive from words that once had neutral or even positive associations. For instance, the word mistress, now mainly used to refer to a woman who is involved in an extramarital sexual relationship, originally served simply as a neutral counterpart to mister or master. The term madam, while still a respectful form of address, has had sexual connotations since the early 1700s and has been used to refer to the owner of a brothel since the early 1900s.