Penal means relating to the punishment of criminals.
例句
...director-general of penal affairs at the justice ministry.司法部刑事处处长...penal and legal systems.刑罚和司法体制
ADJ
（机构或地区）关押服刑人员的
A penal institution or colony is one where criminals are kept as punishment.
例句
...imprisoned on an island that has served as a penal colony since Roman times.被关押在自罗马时代以来就一直作为罪犯流放地的小岛上
英汉词典释义
adj.
与刑罚有关的
After his experience in jail, he has a pretty jaundiced view of the penal system.经历了牢狱生活之后，他对刑罚制度颇有成见。Parliament may legislate on any matter of penal law.议会可以对刑事法律的任何事项立法。The punishments for robbery and murder are prescribed in the penal code.对抢劫和凶杀的惩罚在刑法中有明文规定。