Font Metrics
The main terms and metrics
The main measurements of a character - or their respective technical terms, are:
Baseline, x-height, ascender height, descender depth, body height and cap height.
To find out which is which, and to understand the definitions, have a look at the following illustrations:
1 Ascender height
2 mean line, x-height
3 descender depth (descender height)
The second line from below is the baseline
1 cap height
2 body height, font size