In typography, cap height is the height of a capital letter above the baseline for a particular typeface.[1] It specifically is the height of capital letters that are flat—such as H or I—as opposed to round letters such as O, or pointed letters like A, both of which may display overshoot. The height of the small letters is the x-height.
- ^ http://pfaedit.sourceforge.net/glossary.html Glossary of (some) Typographic Terms