Definition: A serif is the tiny stroke at the end of the main strokes of a font character. A font family that does not have these serifs is called a sans-serif font. Sans-serif fonts are best used online, as they are easier to read there. On the Web serifs can make the fonts more difficult to read, especially at small sizes, but sans-serif fonts do not have this problem.
Pronunciation: san sair if - (adjective)