Definition of "M"

M¹

/ɛm/

letter
upper case, lower case m, plural Ms or M's
1. The thirteenth letter of the English alphabet, called em and written in the Latin script.

M²

number
upper case, lower case m
1. The ordinal number thirteenth, derived from this letter of the English alphabet, called em and written in the Latin script.

M³

noun
countable and uncountable, plural Ms
1. Initialism of mother.
2. Initialism of men (sign on toilet door).
  Quotations
  From the Kierkegaard Room he lopingly careened through a red-carpeted hallway that had previously vouchsafed him a comfort station but this morning seemed all business, no M or W in sight, just salons and boutiques and the Ingmar Bergman Cinema.
  2001, Jonathan Franzen, The Corrections, New York, NY: Farrar, Straus and Giroux, page 332
3. Abbreviation of Monday.
4. Abbreviation of nautical mile.
5. Initialism of million.
6. (entomology) Initialism of media.
7. (usually clothing, singular only) Initialism of medium (the manufactured size or an item of that size).
8. (US, film) A film with the content rating M.
9. (in job listings) Abbreviation of minority.
10. (slang) Initialism of morphine.
  Quotations
  [Doctors] always carry narcotic prescription blanks and some M with them. M is morphine.
  1952, Woman's Home Companion, volume 79, page 141
  “Anyway, when he came out of Patsy's room, I grabbed him by the arm and said, ‘Gee whiz, doc, haven't you got a couple of pills for me—even demerol?’ ” / Willie broke off to explain. “That's a synthetic. We call them demmies. If you can't buy H or M, why, demmies will do the trick.”
  1956, Jess Stearn, Sisters of the Night: The Startling Story of Prostitution in New York Today, New York: Julian Messner, Inc., page 59
  That night Marylou took everything in the books; she took tea, goofballs, benny, liquor, and even asked Old Bull for a shot of M, which of course he didn’t give her; he did give her a martini.
  1957, Jack Kerouac, On the Road, Viking Press
  'You were going to get me some M,' she whispered in his ear. […] His friend uses morphine, too.
  2009, Larry Harrison, Glimpses of a Floating World, page 142
11. (cricket, in batting figures) the number of minutes a player spent at the crease
12. (cricket, in bowling figures) the number of maiden overs bowled
13. (India, Islam, Internet slang) Initialism of Muslim; mostly used by Hindutva netizens primarily towards Islamist supporters and Muslim militants.
14. Initialism of masochist.
  Quotations
  In all the sexual encounters I have participated in or know of the "M" sets the limits as to what to get into and how much pain will be applied. And of course if the scene gets too rough the "M" has the right to stop it.
  1980 April 5, Brian O'Dell, “Sensuality/Mutuality”, in Gay Community News, page 4
noun
plural Messrs or MM
1. Monsieur.
  Quotations
  I also advise reading the Merlin of M Jean Prévost, published by the N. R. F., a swift audacious picture of post-war love, treated with the grace of a Crébillon or of a Restif de la Bretonne. I could not recommend too highly the Petite Histoire des Juifs which MM Jean and Jérôme Tharaud have just published with Plon.
  1928 May, Paul Morand, “Paris Letter”, in The Dial, volume LXXXIV, number 6, published June 1928, page 508
noun
1. (stenoscript) Abbreviation of month.
proper noun
1. (Michigan, roadway) Michigan.
adjective
not comparable
1. Initialism of male.
2. (usually clothing) Initialism of medium (of the manufactured size).
3. Initialism of mature.