An extreme form of pedantry. Latin puns may also be liberally sprinkled to garnish the response. Most geeks are polymaths and will take every opportunity to point out this distinction. Thus a geek on foot will travel at speeds far in excess of normal pedestrians and may even attempt to walk through other people or objects in order to reach a destination. In extreme cases the geek's vehicle may actually be travelling backwards.
Geeks understand and use terms like sic and paradigm in everyday conversations.
Advanced geeks communicate in Fortran, hex, octal or binary. Star Trek fans are called Trekkers. Get these mixed up at your peril. Like the birds that they watch, twitchers are often found in flocks.