1. a member of any of several European churches professing to be truly Catholic but rejecting certain modern Roman Catholic doctrines, dogmas, and practices, esp. the dogma of papal infallibility.
2. a member of any of several minor churches, esp. in the U.S., differing from the Roman Catholic Church chiefly in their rejection of the ecclesiastical authority of the Roman Catholic hierarchy.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.