Definition: In typography, x-height is the distance between the baseline of a line of type and tops of the main body of lower case letters (i.e. excluding ascenders or descenders). The x-height is a factor in typeface identification and readability.
Typefaces with very large x-height relative to the total height of the font have shorter ascenders and descenders and thus less white space between lines of type. Sans Serif typefaces typically have large x-heights. In typefaces with small x-heights, other letter parts such as ascenders and descenders may become more visually noticeable.
Typefaces with large x-heights may appear darker, heavier, crowded, and more difficult to read at body copy sizes.
If changing to a typeface with a smaller x-height is not an option, open up the lines of type by adding more leading (line spacing), and not using fully justified alignment.
Also Known As: xheight
In typography, the x-height or corpus size refers to the distance between the baseline and the mean line in a typeface. Typically, this is the height of the letter x in the font (the source of the term), as well as the u, v, w, and z. (Curved letters such as a, c, e, m, n, o, r and s tend to exceed the x-height slightly, due to overshoot.) However, in modern typography, the x-height is simply a design characteristic of the font, and while an x is usually exactly one x-height in height, in some more decorative or script designs, this may not always be the case.
The height of a lowercase x used to represent the height of the main body of a lowercase letter.