What are the main classes of crime?

The main classes of crime are felonies, misdemeanors, and
infractions.  These are classified according to the seriousness of those
crimes.

Felonies are the most serious crimes and are
generally defined as crimes for which the penalty is more than one year imprisonment. 
These are crimes such as burglary or larceny or even
murder.

Misdemeanors are less serious crimes.  These may be
punishable by a shorter term in a jail or by a fine.  Misdemeanors can include such
things as petty theft or public intoxication.

Finally, some
crimes are classified as infractions.  These are generally very low-level acts that are,
in some places, not even classified as crimes.  These would include such things as
traffic offenses.