castle

From Middle English castle, castel, from late Old English castel, castell (“a town, village”), borrowed from Late Latin castellum (“small camp, fort”), diminutive of Latin castrum (“camp, fort, citadel, stronghold”). Doublet of cashel, castell, castellum, and château.

Parallel borrowings (from Late Latin or Old French) are Scots castel, castell (“castle”), West Frisian kastiel (“castle”), Dutch kasteel (“castle”), German Kastell (“castle”), Danish kastel (“citadel”), Swedish kastell (“citadel”), Icelandic kastali (“castle”), Welsh castell.

The late Old English word was borrowed from biblical Latin castellum which has been translated as town or village. With the sense of castle, from Anglo-Norman/Old Northern French castel (“castle”), itself from Late Latin castellum (“small camp, fort”) (compare modern French château from Old French chastel). If Latin castrum (“camp, fort, citadel, stronghold”) is from Proto-Indo-European *kat- (“hut, shed”), Latin casa (“cottage, hut”) is related. Possibly related also to Gothic 𐌷𐌴𐌸𐌾𐍉 (hēþjō, “chamber”), Old English heaþor (“restraint, confinement, enclosure, prison”). See also casino, cassock.