Definition of Erastian in US English:

Erastian

noun

  • A supporter of the doctrine that the state should have supremacy over the Church in ecclesiastical matters (wrongly attributed to Erastus)

    ‘he was an Erastian who believed in parliamentary control of the Church’

adjective

  • Relating to or supporting the doctrine that the state should have supremacy over the Church in ecclesiastical matters.

    ‘an Erastian view of ecclesiastical authority’

Pronunciation