Cap height
Height of a capital letter above the baseline / From Wikipedia, the free encyclopedia
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.
![Typography Height](http://upload.wikimedia.org/wikipedia/commons/thumb/3/39/Typography_Line_Terms.svg/320px-Typography_Line_Terms.svg.png)