m /ˈɛm/
 字母m
 M
 1. 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. See Guide to Pronunciation, §§ 178-180, 242.
 Note: The letter M came into English from the Greek, through the Latin, the form of the Greek letter being further derived from the Phœnician, and ultimately, it is believed, from the Egyptian. Etymologically M is related to n, in lime, linden; emmet, ant; also to b.
     M is readily followed by b and p. the position of the lips in the formation of both letters being the same. The relation of b and m is the same as that of d and t to n. and that of g and k to ng.
 2. As a numeral, M stands for one thousand, both in English and Latin.
 M, n.
 1. Print. 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. [Written also em.]
 2. law A brand or stigma, having the shape of an M, formerly impressed on one convicted of manslaughter and admitted to the benefit of clergy.
 M roof Arch., a kind of roof formed by the junction of two common roofs with a valley between them, so that the section resembles the letter M.
 ◄ ►
 m
      adj : denoting a quantity consisting of 1,000 items or units [syn:
             thousand, a thousand, one thousand, 1000, k]
      n 1: the basic unit of length adopted under the Systeme
           International d'Unites (approximately 1.094 yards) [syn:
            meter, metre]
      2: concentration measured by the number of moles of solute per
         liter of solvent [syn: molarity, molar concentration]
      3: the cardinal number that is the product of 10 and 100 [syn:
         thousand, one thousand, 1000, K, chiliad, G, grand,
          thou, yard]
      4: the 13th letter of the Roman alphabet