The noun imprisonment has 3 senses (first 1 from tagged texts)
1. (3) imprisonment -- (putting someone in prison or in jail as lawful punishment)
2. captivity, imprisonment, incarceration, immurement -- (the state of being imprisoned; "he was held in captivity until he died"; "the imprisonment of captured soldiers"; "his ignominious incarceration in the local jail"; "he practiced the immurement of his enemies in the castle dungeon")
3. imprisonment, internment -- (the act of confining someone in a prison (or as if in a prison))