ser·if 
(sĕrĭf)
(sĕrĭf)n.
A fine line finishing off the main strokes of a letter, as at the top and bottom of M.
[Perhaps from Dutch schreef, line, from Middle Dutch scrēve, from scriven, to write, from Latin scrībere; see skrībh- in the Appendix of Indo-European roots.]
serifleft: serif typeface
right: sans serif typeface