Of, relating to, or involving punishment, as for crimes or offences. (Dictionary.com)
Prescribing punishment: (Dictionary.com)
Constituting punishment: (Dictionary.com)
Of or relating to punishment given by law. (Cambridge Dictionary)
Of, relating to, or involving punishment, penalties, or punitive institutions. (Merriam -Webster)
Liable to punishment. (Merriam – Webster)
Used as a place of confinement and punishment. (Merriam – Webster)
Penal means relating to the punishment of criminals. (Collins Dictionary)
A penal institution or colony is one where criminals are kept as punishment. (Collins Dictionary)
International Review of Penal Law.
A Global History of Convicts and Penal Colonies.
The Lords of Discipline. The Penal Colony Guards of New Caledonia.