Fountain of Knowledge

Ariana,

While I was confident of the answer, I didn't find a great reference. "Ms." is not short for any particular word, so is never spelled out. Most dictionaries have an entry for "Ms." Wikipedia has a great entry on Ms. AT the end of this post I have one example from answers.com

I know that numbers are spelled out, but I would never spell out "Mr." or "Mrs." I was surprised to find that my Strunk & White didn't provide an answer. So I did some sleuthing, and it was hard to find anything definitive. I did find this from "Elements of Rhetoric: A Course in Plain Prose Composition" by Alfonso Newcomer of Stanford University. (OK, so it was published in 1899...sue me!)


"Mr., Mrs., Messrs., Dr., Pres., Prof., Rev......All of the titles, except the first four, should be spelled out...


From answers.com:
also Ms n., pl. Mses. also Mses also Mss. or Mss (mĭz'ĭz).
Used as a courtesy title before the surname or full name of a woman or girl: Ms. Doe; Ms. Jane Doe.
Used in informal titles for a woman to indicate the epitomizing of an attribute or activity: Ms. Fashionable; Ms. Volleyball.
[Blend of MISS and MRS..]

USAGE NOTE Many of us think of Ms. or Ms as a fairly recent invention of the women's movement, but in fact the term was first suggested as a convenience to writers of business letters by such publications as the Bulletin of the American Business Writing Association (1951) and The Simplified Letter, issued by the National Office Management Association (1952). Ms. is now widely used in both professional and social contexts. As a courtesy title Ms. serves exactly the same function that Mr. does for men, and like Mr. it may be used with a last name alone or with a full name. Furthermore, Ms. is correct regardless of a woman's marital status, thus relegating that information to the realm of private life, where many feel it belongs anyway. Some women prefer Miss or Mrs., however, and courtesy requires that their wishes be respected.