—used as a conventional title of courtesy before a woman's surname
My history teacher is Ms. Judson
—used instead of Miss or Mrs. (as when the marital status of a woman is unknown or irrelevant)
Ms. Mary Smith"I think you do want to dispute the fact that you had a difficult childhood," Ms. Johnston told Mrs. Gore, who was silent for several beats, then agreed. Katha PollittBut it wasn't until the 1970s that Ms. took its place in the emerging women's liberation movement. It was a heady time for women, and the new prefix represented an important new way for them to define themselves as individuals, rather than in terms of their relationship to men. Carol Toller