M.

M. (plural Mm.)

1. Alternative letter-case form of m.

From French M..

M. (plural Messrs. or MM.)^[1]

1. Alternative form of M (“Monsieur”).
   • 1816 June – 1817 April/May (date written), [Mary Shelley], chapter II, in Frankenstein; or, The Modern Prometheus. […], volume I, London: […] [Macdonald and Son] for Lackington, Hughes, Harding, Mavor, & Jones, published 1 January 1818, →OCLC, page 69:

     The next morning I delivered my letters of introduction, and paid a visit to some of the principal professors, and among others to M. Krempe, professor of natural philosophy.

   • 1823, Adam Hodgson, A Letter to M. Jean-Baptiste Say: On the Comparative Expense of Free and Slave Labour:
   • 1885, The Era Almanack and Annual, page 79:

     Hérodiade, opera, in four acts, libretto by MM. Paul Milliet and Gremont, music by M. Jules Massenet, February 1.

• “M.”, in Collins English Dictionary: “M. in British English / ABBREVIATION FOR […] Monsieur”

From Ms., Mrs., Mr., Miss, Mister, Mistress, Master, Magistrate, Missus.

• IPA^(key): /ɛm/

M.

1. (rare) A gender-neutral honorific, comparable to Mx., used instead of Mr., Mrs., etc.
   • 1982 July 10, Mx. John Eldridge (username "floyd!jce"), More words and sex, net.nlang:

     while we're at it, let's get rid of all this Miss/Mrs/Mr/Ms crap. It wasn't much of a step to go from Miss/Mrs to Ms; after all, the issue should be that gender is unimportant. How about one generic title for everyone? For instance, M. Smith, M. Jones. […]

   • 1983 September 27, Martin Taylor, Miss/Mrs/Ms, net.women:

     I like the idea of just "M. Smith". Who cares whether the person is male or female if the matters under discussion are just business? If this is confusable with "Malcolm Smith" or "Marylin Smith", why not use "Mx. Smith" instead. […]

Abbreviation

M.

1. Abbreviation of model.

   Coordinate terms: M-, M

• IPA^(key): /mə.sjø/

• Audio:

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M. m (plural MM.)

1. Abbreviation of Monsieur.

   Synonym: M^r

• In modern standard French as spoken in France, the usual abbreviation of monsieur is M., and its plural, the abbreviation of messieurs, is MM. Uncommonly, Mr (and archaically Mr.) is found as an alternative abbreviation of monsieur; its plural is Mrs. In older French, especially in Louisiana, Guernsey and elsewhere, Messrs (and Messrs.) was found as an alternative plural, i.e. an alternative abbreviation of messieurs.

• M^dlle
• M^lle
• Mlle.
• M^me
• Mme.

M. m (indeclinable)

1. Praenominal abbreviation of Marcus.
2. (rare) Praenominal abbreviation of Manius.