Deterrence refers to a strategy of punishment associated with the Classical School. Deterrence can either be specific, punishing an individual so that she won't commit a crime again, or general, punishing an individual to set an example to society, so that others will not commit the same crime. For the Classical School, punishment was primarily justified in terms of general deterrence.
Deterrence refers to the prevention of crime.
Other /More definition:
Deterrence refers to the theory of punishment which envisages that potential offenders will refrain from committing crimes out of fear of punishment sometimes called general prevention.
List of books: Deterrence