Unit of relative distance in typography, one en being equivalent to one-half of an em or point size of the type. In 8 point type, an en is 4 point wide; in 9 point type, 4.5 point wide; in 10 point type, 5 point wide ... and so on. So named because traditionally it is defined as the width of a capital (uppercase) letter 'N' in the face and point of type being used.