A custodial sentence is a judicial sentence, imposing a punishment (and hence the resulting punishment itself) consisting of mandatory custody of the convict, either in prison (incarceration) or in some other closed therapeutic and/or (re)educational institution, such as a reformatory, (maximum security) psychiatry or drug detoxication (especially cold turkey).

Although usually not labeled as such (at hence not in the legal sense) it can be considered a type of corporal punishment, even if no further physical punishments are practiced within the institution (these can also be informal, without any rights of defense), since it constitutes a physical coercion. Indeed the technical term duress is equally used for loss of liberty and for coercion.

The concept of penal harm (see that article) often induces additional elements of physical endurance.

Every other sentence and punishment is non-custodial, such as fines, judicial beatings, various mandatory but 'open' therapy and courses, restriction orders, loss or suspension of civil rights, or even suspended sentences.