Webster's Revised Unabridged Dictionary · 1913

Dissenter

Dissenter , noun

1.
One who dissents; one who differs in opinion, or declares his disagreement.
2.
(Ecclesiastical) One who separates from the service and worship of an established church; especially, one who disputes the authority or tenets of the Church of England; a nonconformist.
Dissenters from the establishment of their several countries. — Burke
Robert Brown is said to have the first formal dissenter. — Shipley

“The word is commonly applied only to Protestants. The Roman Catholics are generally referred to as a distinct class.”