em

1 of 3

noun

ˈem 

1

: the letter m

2

: the width of a piece of type about as wide as it is tall used as a unit of measure of typeset matter

EM

2 of 3

abbreviation

1

electromagnetic

2

electron microscope; electron microscopy

3

end matched

4

engineer of mines

5

enlisted man

em-

3 of 3

prefix

see en-

Word History

First Known Use

Noun

13th century, in the meaning defined at sense 1

Kids Definition

em-

see en-

Medical Definition

EM

abbreviation

1

electromagnetic

2

electron microscope; electron microscopy

3

emergency medicine