noun
(Christianity) An itinerant or special preacher, especially a revivalist, who conducts services in different cities or locations, now often televised.
(biblical) A writer of a gospel, especially the four New Testament Gospels (Matthew, Mark, Luke, and John), usually capitalized (Evangelist).
(primitive Church) A person who first brought the gospel to a city or region.
(Church of Jesus Christ of Latter-day Saints) A patriarch.
(by extension) A person marked by extreme enthusiasm for or support of any cause, particularly with regard to religion.
(technology) A person hired to promote a particular technology.