from The American Heritage® Dictionary of the English Language, 5th Edition.

  • abbreviation Grammar masculine
  • abbreviation Physics mass
  • abbreviation meter (measurement)
  • abbreviation mile
  • abbreviation minute
  • abbreviation Physics modulus
  • abbreviation Chemistry molality
  • noun The 13th letter of the modern English alphabet.
  • noun Any of the speech sounds represented by the letter m.
  • noun The 13th in a series.
  • noun Something shaped like the letter M.

from The Century Dictionary.

  • noun An abbreviation of Middle Latin or Medieval Latin.
  • noun An abbreviation of mean time.
  • noun An abbreviation of Maelzel's metronome. See metronome.
  • noun An abbreviation of Member of Parliament.
  • noun An abbreviation
  • noun of Master of Horticulture;
  • noun of Most Honorable.
  • An abbreviation
  • of Master of Laws;
  • of Master of Literature;
  • of muzzle-loading.
  • As a symbol:
  • M denotes magnetic moment: usually printed in old English; a gaseous pressure of the millionth of an atmosphere.
  • μ denotes magnetic permeability or the specific conductivity of any substance for lines of magnetic force; the coefficient of friction.
  • m stands for the intensity or strength of a magnetic pole.
  • m stands for square meters, m for cubic meters.
  • As an abbreviation:
  • In titles, M. stands also for Marquis, Matthew (a book of the New Testament), and Monsieur.
  • In a ship's log-book, masculine is an abbreviation of moderate.
  • In a chart, masculine stands for mud; in meteorology, for mist; in ophthalmol., for myopia.
  • In pharmacy, M. or masculine stands for macerare (macerate), manipulus (a handful), mensura (measure or by measure), minimum (minim), misce (mix), mistura (mixture).
  • In astronomical tables, M. or masculine (abbreviation of L. meridies) indicates meridian or meridional: 12 M. stands for noon. See A. M. and P. M.
  • In astronomy, M. stands for Messier, referring to his catalogue of 103 nebulæ and star-clusters: thus, 51M. or M.51 is the famous whirlpool nebula.
  • M. stands for Monday; M. or masculine, for mile or miles, mill or mills, month or months, moon, muster; m., for married, masculine, middle, minutes, morning, and the Latin mille (a thousand).
  • noun An abbreviation
  • noun of Master of Painting;
  • noun of man-power;
  • noun of Member of Police;
  • noun of Methodist Protestant;
  • noun of Metropolitan Police;
  • noun of the Latin millia passuum, a thousand paces: the Roman mile;
  • noun of Municipal Police.
  • The thirteenth letter and tenth consonant in the English alphabet.
  • As a numeral, in the Roman system, M denotes 1,000. With a dash or stroke over it (M), it stands for a thousand times a thousand, or 1,000,000.
  • As a symbol
  • In the mnemonic words of logic (see mood), m indicates a transposition (metathesis) of the premises in the reduction.
  • Formerly, M was a brand impressed on one convicted of manslaughter and admitted to the benefit of clergy.
  • As an abbreviation
  • In titles, M. stands for Magister or Master, as in A. M.; for Medicinæ or Medicine, as in M. D.; or for Member, as in M. C, member of Congress, and M. P., member of Parliament.


from Wiktionary, Creative Commons Attribution/Share-Alike License

From upper case roman numeral M (1000), an alteration of ⋈, from ∞, an alteration of ↀ, an alteration of Ⓧ, from encircling X (the roman numeral for ten) to indicate the hundredth ten.

from Wiktionary, Creative Commons Attribution/Share-Alike License

Modification of capital letter M, from Ancient Greek letter Μ (M, "Mu").

from Wiktionary, Creative Commons Attribution/Share-Alike License

Various abbreviations


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  • "I learned from Florey that the Egyptians used a wavelike symbol for water that the Phoenicians adapted and called mem—thus the letter M. I loved the soothing mindlessness of the exercises, particularly seeing the mmmm's break across the page—a tiny, rolling sea."

    —Emily Yoffe, "Dead Letters: Everyone Has Terrible Handwriting These Days,", seen here.

    September 12, 2009

  • Txt/twitterspeak for "am"

    September 30, 2015