Typographic Terminology

Baseline The baseline is an imaginary line upon which each character rests. Characters that appear next to each other are usually lined up so that their baselines are on the same level. Some characters extend below the baseline (g and j, for example) but most rest on it.

X-Height Traditionally, x-height refers to the height of the lowercase letter x. It is the same for all lowercase letters in a font, excluding the ascenders and descenders. Notice that some lower-case letters that do not have ascenders or descenders may still extend a little bit above or below the x-height as part of their design. The x-height can vary greatly from typeface to typeface, even at the same point size.

Cap Height Height from the baseline in any font to the top of most capitals. Note that well-formed rounded characters, like O, Q and S, often are taller than other caps, and may drop below (dent) the baseline; this is considered good practice, making them more legible. The cap height does not necessarily coincide with the ascending line of ascending lowercase letters.

Point Size Method of measuring the size of type, commonly known as font size. It measures the distance from the top of the highest ascender to the bottom of the lowest descender in points. In Europe, type is often measured by the cap-height in millimeters. 1 inch = 12 picas = 72 points = 25.4 mm