|The height from the baseline to the top of lowercase x.|
|The imaginary horizontal line indicating where the tops of lowercase letters that have no ascenders appear to align. The upper boundary of x-height.|
|XSF (eXcellent Screen Font):|
|Linotype has introduced a special hinting procedure (see Hinting) with eXcellent Screen Font.|
Fonts with XSF hinting are optimised in a complex procedure. This results in fonts with an excellent screen readability especially for Office applications. Linotype offers a selection of OpenType and TrueType fonts with the predicate eXcellent Screen Font (XSF).