Erastianism definitions Webster's 1828 Dictionary ERAS'TIANISM, n. The principles ... state is supreme over the church in ecclesiastical matters [syn: Erastianism, Byzantinism, Caesaropapism] Merriam Webster's noun see Erastian Webster's 1913 Dictionary Erastianism E*ras"tian*ism, n. (Eccl. Hist.) The principles of ...