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