Penal means relating to the punishment of criminals.
例句
...director-general of penal affairs at the justice ministry.司法部刑事處處長...penal and legal systems.刑罰和司法體制
ADJ
（機構或地區）關押服刑人員的
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.被關押在自羅馬時代以來就一直作為罪犯流放地的小島上
英漢詞典釋義
adj.
與刑罰有關的
After his experience in jail, he has a pretty jaundiced view of the penal system.經歷了牢獄生活之后，他對刑罰制度頗有成見。Parliament may legislate on any matter of penal law.議會可以對刑事法律的任何事項立法。The punishments for robbery and murder are prescribed in the penal code.對搶劫和兇殺的懲罰在刑法中有明文規定。