Serif and sans serif stand off against one another in the argument over readability, legibility and relevance – but the truth is that each has its time and place. Further exploring the terminology and history of serif and sans serif can help you better understand their differences, similarities and how to pair them for your projects.When and How to Mix Serif and Sans Serif
The most commonly accepted uses in print include using serif for body text and sans serif for short bursts of copy like headings or captions. Sans can also be used for small text, because it doesn’t smear as badly. Serif is typically avoided for large signs or anything that requires large copy, because the extra emphasis is not needed with oversized text.

Examples of “Serif” (please see link for explanation)