prison

Prison comes from Middle English prisoun, from Old English prisūn, borrowed from Old French prison, which traces back to Latin prehensiō, meaning 'a seizing' — from the verb prehendō, 'to grasp or seize.'

The word's root was simply the act of seizing; over time, as it passed from Latin into Old French and then into English, it settled into naming the place where the seized are kept, rather than the act itself.

Prison is a doublet of prehension, another English descendant of the same Latin verb prehendō — one word kept the sense of grasping, the other became the place you end up after being grasped.