From Middle English enclosen, inclosen, from Middle English enclos, from Old French enclose, feminine plural past participle of enclore, from Vulgar Latin *inclaudō, *inclaudere, from Latin inclūdō (doublet of include), from in- (“in”) + claudō (“to shut”), ultimately from Proto-Indo-European *kleh₂u- (“key, hook, nail”). Equivalent to en- + close.