plural m's or ms
ˈemz 
often capitalized, 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
a
b
1
male
2
manual
3
married
4
martyr
5
masculine
6
mass
7
measure
8
meridian
9
[Latin meridies]
noon
10
meter
11
middle
12
mile
13
[Latin mille]
thousand
14
milli-
15
minute
16
molal; molality
17
mole
18
month
19
moon
20
morning
21
muscle
1
Mach
2
magnitude
3
March
4
May
5
medium
6
mega-
7
million
8
molar; molarity
9
monsieur
meta-
Cite this Entry
“M.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/m. Accessed 18 Apr. 2025.
Copy CitationMedical Definition
m
1 of 4 abbreviation1
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 abbreviation1
[Latin misce]
mix
—used in writing prescriptions
2
mitosis see m phase
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