The Collaborative International Dictionary of English v.0.48:

Archpriest \Arch`priest"\, n.
   A chief priest; also, a kind of vicar, or a rural dean.
   [1913 Webster]

WordNet (r) 3.0 (2006):

archpriest
    n 1: a senior clergyman and dignitary [syn: archpriest,
         hierarch, high priest, prelate, primate]