X-Height

The distance from the

Baseline to the top of flat lowercase letters such as x, z, and v (hence the name). X-height is the single most influential metric for perceived text size and on-screen

Legibility: two

Typeface set at the same point size can appear dramatically different in scale if their x-heights diverge. A generous x-height generally improves

Readability at small sizes but reduces the relative prominence of

Ascender and

Descender, affecting the overall texture of a text block.