These words refer to the shutting up, usually of people, in a particular place. Confine is the most general of these and indicates a reduction of mobility for whatever reason: He felt confined and claustrophobic in a big city; confined by ill-health to her bed. More pertinent to this context, the word suggests removing someone to a prison or mental hospital, usually against the person’s will: a sentence confining him to life imprisonment; a court order confining him indefinitely to an institution for the criminally insane. From one sense of being kept in bed, confine is used (usually in the passive voice) to mean being brought to bed pending the birth of a child: She was confined in the local hospital, awaiting her fifth baby.

The directness and informality of gaol makes confine sound euphemistic by comparison when it refers to shutting someone up in prison: gaoled on a disorderly-conduct charge. Although identical in meaning to gaol , imprison gives more formal tone without sounding euphemistic like confine : a régime that imprisoned anyone suspected of dissent. The one possible difference between gaol and impri son is that gaol might be used for a relatively short stay: gaoled overnight because he had trouble raising bail; imprisoned for ten years in the Bastille. Incarcerate is the most formal of all these words; while close in meaning to imprison , it may suggest the initial act of imprisoning : He was incarcerated in the local gaol pending transfer to a maximum-security prison. Incarcerated is sometimes used to suggest a harsh, punitive or brutal imprisoning under inhumane conditions: They incarcerated him in a windowless basement cell. The word, furthermore, can refer like confine to the shutting up of the mentally ill; here the emphasis may be on inhumane treatment: The family incarcerated the wretch in a concealed, airless room in the attic.

Intern is unique among this group, in pertaining to the impounding of people or even equipment, as during war: the policy of interning citizens of German origin during World War II. The word, furthermore, contrasts sharply with the punitive possibilities of gaol , imprison and incarcerate , in that the interning can conceivably be done for the internee’s own good: They interned the demonstrators to protect them from the fury of the mob.