The font-family property hold several font names . CSS3 has adapted font combinations technology. In here,if the browser doesn’t support the first font then it tries the next font .

Below are some commonly used font combinations

Serif Fonts

Georgia, serif

“Palatino Linotype”, “Book Antiqua”, Palatino, serif

“Times New Roman”, Times, serif

Sans-Serif Fonts

Arial, Helvetica, sans-serif

“Arial Black”, Gadget, sans-serif

“Comic Sans MS”, cursive, sans-serif

Impact, Charcoal, sans-serif

“Lucida Sans Unicode”, “Lucida Grande”, sans-serif

Tahoma, Geneva, sans-serif

“Trebuchet MS”, Helvetica, sans-serif

Verdana, Geneva, sans-serif

Monospace Fonts

“Courier New”, Courier, monospace
“Lucida Console”, Monaco, monospace

A complete collection of web safe CSS font stacks.

http://www.cssfontstack.com/