Ms | Define Ms at Dictionary.com

Ms. came into use in the 1950s as a title before a woman's surname when her marital status was unknown or irrelevant. In the early 1970s, the use of Ms. was adopted and encouraged by the women's movement, the reasoning being that since a man's marital status is not revealed by the title Mr., there is no reason that a woman's status should be revealed by her title. Since then Ms. has gained increasing currency, especially in business and professional use. Some women prefer the traditional Miss (still fully standard for a woman whose marital status is unknown and for an unmarried woman) or, when appropriate, Mrs. Newspaper editors sometimes reject Ms. except in quoted matter. Others use whichever of the three titles a woman prefers if her preference is known. Increasingly, newspapers avoid the use of all three titles by referring to women by their full names in first references (Sarah Brady; Margaret Bourke-White) and by surname only, as with men, in subsequent references: Brady, Bourke-White. Since all three titlesMs., Miss, and Mrs.remain in use, the preference of the woman being named or addressed or the practice of the organization or publication in which the name is to appear is often followed.

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Ms | Define Ms at Dictionary.com