There is no discernible difference between citations and traffic tickets. Both terms can be used interchangeably to describe the notice given to people who commit an infraction.
An infraction is typically a minor crime where the law is broken in a non-violent way. More serious crimes are classified as misdemeanors or felony crimes. A citation or traffic ticket can be given for a wide variety of infractions committed while driving a vehicle. Some common traffic infractions are running a red light, having an expired license, or failure to completely stop at a stop sign. Infractions can be appealed or simply paid.