M, the thirteenth letter of the English alphabet, is a vocal consonant, and from the manner of its formation, is called the labio-nasal consonant.
As a numeral, M stands for one thousand, both in English and Latin.
A quadrat, the face or top of which is a perfect square; also, the size of such a square in any given size of type, used as the unit of measurement for that type: 500 m's of pica would be a piece of matter whose length and breadth in pica m's multiplied together produce that number.
A brand or stigma, having the shape of an M, formerly impressed on one convicted of manslaughter and admitted to the benefit of clergy.
Webster's Revised Unabridged Dictionary (1913), edited by Noah Porter. About