Want to learn about typefaces and fonts? Here is a vocabulary and infographic for the anatomy of a font.
Baseline: the line that the letter sits on.
Median: the middle line where lowercase letters end.
Cap Height: the line where capital letters end.
X Height: the distance between baseline and median, traditionally 60 % of the total height of the cap height.
Ascender: the part of a lower case letter that extends above the median.
Ascender Height: the line where ascenders end, only slightly above the cap height
Descender: the part of a lower case letter that goes below the baseline (as in g and p).
Serif: a typestyle that has a finishing stroke that crosses or projects from stems or strokes in a character. Serifs have many shapes including, bracketed, wedge, hairline and slab.
San Serif: a typestyle that is without or has a lack of serifs.
Visual Alignment: Designers do not depend on alignment being mathematically precise. Spacing between letters and lines of type is all in the eye of the beholder. Nudging here and there makes for better optical alignment and creates a mood, so to speak.