(1):
(a.) Of or pertaining to punishment, to penalties, or to crimes and offenses; pertaining to criminal jurisprudence
(2):
(a.) Enacting or threatening punishment; as, a penal statue; the penal code.
(3):
(a.) Incurring punishment; subject to a penalty; as, a penalact of offense.
(4):
(a.) Inflicted as punishment; used as a means of punishment; as, a penal colony or settlement.