Culdee (n.)

member of an irregular monastic order of priests in the Middle Ages in the Celtic lands of the British Isles, mid-12c., from Old Irish céle de "anchorite," from cele "associate, companion," sometimes "servant" (compare ceilidh) + de "of God." Perhaps an attempt to translate Servus Dei or some other Latin term for "religious hermit." Related: Culdean.