prison (n.) Look up prison at
early 12c., from Old French prisoun "captivity, imprisonment; prison; prisoner, captive" (11c., Modern French prison), altered (by influence of pris "taken;" see prize (n.2)) from earlier preson, from Vulgar Latin *presionem, from Latin prensionem (nominative prensio), shortening of prehensionem (nominative *prehensio) "a taking," noun of action from past participle stem of prehendere "to take" (see prehensile). "Captivity," hence by extension "a place for captives," the main modern sense.
prison (v.) Look up prison at
"to imprison," early 14c., from prison (n.) or Old French prisoner (v.). Related: Prisoned; prisoning.