Chances are good that you’ve looked through the dozens of fonts installed on your computer and seen the word ‘serif’ or ‘sans serif’ and at some point wondered what in the wold these words actually mean. The short answer is these are two distinct kinds of typefaces. But, how do you tell the difference? This short article will explain what a serif is and how to identify if you are using a serif or sans serif typeface. 
Serif Fonts
A serif is actually the little pointy foot at the top or bottom of a character in a more formal typeface like Times. Note the example to the right. The capitol M has little feet at the top and bottom of the letters. These feet are called serifs. The origins of the word serif are a little murky and a topic I’ll devote to a separate article. However, serifs, the little feet, came into our English characters from the Roman equivalents. Most likely the Roman alphabet was pulled from Phoenician which borrowed from both Akkadian and Egyptian. Again, these origins are fascinating and I hope to write more on that later.
Here are a few interesting links about serifs:
http://en.wikipedia.org/wiki/Serif
http://ilovetypography.com/2007/08/26/who-shot-the-serif-typography-terms/
http://www.worldlingo.com/ma/enwiki/en/Serif
Sans Serif Fonts
The word Sans simply means ‘without.’ So, a Sans Serif character is one without the little feet. These typefaces are considered ‘modern’ having come about well after Roman characters with the advent of the printing press and modern typesetting. Some of the more common fonts you’ll find without the feet, or serifs, would be Helvetica or Ariel. Ariel is pretty much Microsoft’s answer to Helvetica. Notice the typeface is streamlined with the removal of the feet.
Here are some links to info about san serif fonts:
http://en.wikipedia.org/wiki/Sans-serif
http://www.alexpoole.info/academic/literaturereview.html
http://www.chacha.com/content/infographics/Origin-of-important-typefaces
Of course there are many other types of fonts out there, but the two largest categories fall into serif or sans serif categories. Hopefully this short guide will help in determining which you are working with.