Definition - What does Serif mean?
A serif is a graphic design component of text characters that dates back to early Roman times. It is described as a short line or appendage joined to individual letters in text. This gives the letters and numbers a particular type of visual style that is still popular in modern fonts.
Techopedia explains Serif
Modern font families are described as either “serif” or “sans serif.” Serif fonts have small line appendages on most of the alphabet's letters, for example, at the ends and bottom of a letter T, or at both ends of the letter Z. Other types of fonts are described as sans serif – these do not have any line appendages, but consist of a single line, as in letters like C, S and L, or a line terminating at the beginning of another line used to draw the letter, in complex letters like E, F and X.
Historians describe the contrast between serif and sans serif fonts as "Roman" and "Gothic" – the Latin or Roman font, for example, Times New Roman, uses the serif, while Gothic fonts like Calibri do not.