n. (pl. Ms or M's)
1 the thirteenth letter of the alphabet.
2 (as a Roman numeral) 1,000.
2.
abbr. (also M.)
1 Master.
2 (in titles) Member of.
3 Monsieur.
4 (in the UK in road designations) motorway.
5 mega-.
6 Chem. molar.
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M(ɛm)
the thirteenth letter of the modern and twelfth of the ancient Roman alphabet, represents historically the Greek mū and the Semitic mēm. The Phœnician form of the letter is
Useful english dictionary. 2012.