Notes on the Canons of Nicaea

catechumens	those receiving instruction, preparing to join the church.
hearers	they could listen to the service from outside of the assembly.
lapsi	the technical term for those who during persecution either renounced or abandoned the faith, but after persecution sought re-admission to the church.
metropolitan bishop	the bishop of the nearest metropolis, e.g. Rome, Alexandria, Carthage, or Antioch.
prostrators	they could stay within the church but had to leave with the catechumens