Definitions for "Em Space"
Keywords:  mutton, width, font, typeface, space
A space (between words) that will have its width equal to either the width of a capital letter "N" or "M."
A space equal to the width of the lower case letter "m".
A measure of distance equal to the body of a capital. In linear measure, a distance equal to the type size, and in square measure, the square of the type size. Thus an em is 12pt (or a 12pt square) in 12pt type. Also called mutton.