Penology is a section of criminology

Criminology

Criminology is the scientific study of the nature, extent, causes, and control of criminal behavior in both the individual and in society...

 that deals with the philosophy and practice of various societies in their attempts to repress criminal activities, and satisfy public opinion via an appropriate treatment regime for persons convicted of criminal offenses.

The Oxford English Dictionary

Oxford English Dictionary

The Oxford English Dictionary , published by the Oxford University Press, is the self-styled premier dictionary of the English language. Two fully bound print editions of the OED have been published under its current name, in 1928 and 1989. The first edition was published in twelve volumes , and...

 defines penology as "the study of the punishment of crime and prison management", and in this sense it equivalent with corrections

Corrections

In criminal justice, particularly in North America, correction, corrections, and correctional, are umbrella terms describing a variety of functions typically carried out by government agencies and involving the punishment, treatment, and supervision of persons who have been convicted of crimes....

.

Penology is concerned with the effectiveness of those social processes devised and adopted for the prevention of crime

Crime

Crime is the breach of rules or laws for which some governing authority can ultimately prescribe a conviction...

, via the repression or inhibition of criminal intent via the fear of punishment

Punishment

Punishment is the authoritative imposition of something negative or unpleasant on a person or animal in response to behavior deemed wrong by an individual or group....

.