Meaning of EM in English

I. ˈem noun

( -s )

1. : the letter m

2. : the set dimension of an em quad used as a unit of measure

3. : pica

II. adjective

1. : having the form of capital M

an em fold

2. : of the size of an em

an em dash

a 24 em line of type

III. abbreviation

1. emanation

2. eminence

Webster's New International English Dictionary.      Новый международный словарь английского языка Webster.