Locked up in prison or confined, unable to leave or escape from a place.
From Old French 'emprisoner,' combining 'en-' (put in) and 'prison' (prison). The word evolved as criminal justice systems developed and prisons became formal institutions for punishment.
The concept of locking people in buildings as punishment is actually quite modern—for most of human history, criminals faced fines or physical punishment instead, and 'imprisonment' became common only when governments could build and maintain large buildings.
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