 "Carusburg" would mean "fortress of the marsh" in Old Norse "kjarr" (marsh), and "borg" (castle, fortified town) or "city of the marais" in Old English "ker" (bog) and "burgh" (town).The element "kjarr" / "ker" is also found in Normandy in Villequier and Orcher.According to François de Beaurepaire, it comes rather from the Old English "chiriche" (spelled "ċiriċe", Church) or [tch] is reduced to [s], as the commune of Chirbury, in the County of Shropshire, formerly also spelled "Chirichburig" (915) and "Chiresbir" (1226).