variants often M
plural m's or ms ˈemz How to pronounce m (audio)
often attributive
1
a
: the 13th letter of the English alphabet
b
: a graphic representation of this letter
c
: a speech counterpart of orthographic m
2
: one thousand see Table of Numbers
3
: a graphic device for reproducing the letter m
4
: one designated m especially as the 13th in order or class
5
: something shaped like the letter M
6

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Words Starting With M

Browse 19,456 words and phrases that start with the letter M, from ma to myzostome.

Did you know?

Words Starting With M

Browse 19,456 words and phrases that start with the letter M, from ma to myzostome.

Did you know?

Words Starting With M

Browse 19,456 words and phrases that start with the letter M, from ma to myzostome.

Examples of m in a Sentence

a word that starts with an m a word that starts with m

Word History

First Known Use

before the 12th century, in the meaning defined at sense 1a

Time Traveler
The first known use of m was before the 12th century

Browse Nearby Words

Cite this Entry

“M.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/m. Accessed 9 Jun. 2026.

Kids Definition

m

noun
often capitalized
1
: the 13th letter of the English alphabet
2
: one thousand in Roman numerals

Medical Definition

m

1 of 4 abbreviation
1
Mach
2
male
3
married
4
masculine
5
mass
6
meter
7
[Latin mille] thousand
8
million
9
minim
10
minute
11
molal
12
molality
13
molar
14
molarity
15
mole
16
mucoid
17
muscle

m-

2 of 4 abbreviation
meta-

M

3 of 4 noun
plural M's or Ms
: an antigen of human blood that shares a common genetic locus with the N antigen

M

4 of 4 abbreviation
1
[Latin misce] mix
used in writing prescriptions
2
mitosis see m phase

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