Indices : Terminology : Aperture

An “aperture” is a constricted opening of a Glyph. For example, the lowercase “e” has an aperture at 4 o’clock. This aperture is relatively small in some fonts (such as Avant Garde) and much larger (or more open) in others (such as Frutiger). It is widely believed that a relatively large aperture helps readability.

See also Counter.