Mrs

Mrs. originated as a contraction of the honorific Mistress (the feminine of Mister or Master) which was originally applied to both married and unmarried women in the upper class. Writers who used Mrs for unmarried women include Daniel Defoe, Samuel Richardson, Henry Fielding, and Samuel Johnson. The split into Mrs for married women and Miss for unmarried began during the 17th century, but was not reliable until well into the 19th century.