The Collaborative International Dictionary of English v.0.48:
Erastianism \E*ras"tian*ism\, n. (Eccl. Hist.) The principles of the Erastains. [1913 Webster]WordNet (r) 3.0 (2006):
Erastianism n 1: the doctrine that the state is supreme over the church in ecclesiastical matters [syn: Erastianism, Byzantinism, Caesaropapism]