If people are incarcerated, they are kept in a prison or other place. They were incarcerated for the duration of the war It can cost $40,000 to $50,000 to incarcerate a prisoner for a year. = imprison + incarceration in·car·cera·tion her mother's incarceration in a psychiatric hospital. = imprisonment. to put or keep someone in prison = imprison (past participle of incarcerare, from carcer )