apostle

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One of a group made up especially of the 12 disciples chosen by Jesus to preach the gospel.
• noun A missionary of the early Christian Church.
• noun A leader of the first Christian mission to a country or region.
• noun One of the 12 members of the administrative council in the Mormon Church.
• noun One who pioneers an important reform movement, cause, or belief.
• noun A passionate adherent; a strong supporter.

from The Century Dictionary.

• noun A person sent to execute some important business: among the Jews of the Christian epoch, a title borne by persons sent on foreign missions, especially by those commissioned to collect the temple tribute; specifically adopted by Christ as the official title of twelve of his disciples chosen and sent forth to preach the gospel to the world (Luke vi. 13); afterward applied in the New Testament to others who performed apostolic functions, as Paul and Barnabas, and once to Christ himself (Heb. iii. 1).
• noun In the Mormon Ch., the title of an official whose duty it is to be a special witness of the name of Christ, to build up and preside over the church, and to administer in all its ordinances.
• noun In the liturgy of the early church, and in the modern Greek Church, the lesson from the epistles, usually taken from the writings of St. Paul; also, a book containing these lessons, printed in the order in which they are to be read.
• noun In law, a brief statement of a case sent by a court whence an appeal has been taken to a superior court.
• noun Nautical, a knighthead or bollard-timber where hawsers and heavy ropes are belayed.

from the GNU version of the Collaborative International Dictionary of English.

• noun Literally: One sent forth; a messenger. Specifically: One of the twelve disciples of Christ, specially chosen as his companions and witnesses, and sent forth to preach the gospel.
• noun The missionary who first plants the Christian faith in any part of the world; also, one who initiates any great moral reform, or first advocates any important belief; one who has extraordinary success as a missionary or reformer.
• noun (Civ. & Admiralty Law) A brief letter dimissory sent by a court appealed from to the superior court, stating the case, etc.; a paper sent up on appeals in the admiralty courts.
• noun a creed of unknown origin, which was formerly ascribed to the apostles. It certainly dates back to the beginning of the sixth century, and some assert that it can be found in the writings of Ambrose in the fourth century.
• noun (Antiq.) a spoon of silver, with the handle terminating in the figure of an apostle. One or more were offered by sponsors at baptism as a present to the godchild.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun law A letter dismissory.
• noun law A note sent to an appeal court presenting the appeal in summary.
• noun law The trial court record sent to an appeal court concerning an appeal.
• noun A missionary, or leader of a religious mission, especially one in the early Christian Church (but see Apostle).
• noun A pioneer or early advocate of a particular cause, prophet of a belief.
• noun A top-ranking ecclesiastical official in the twelve seat administrative council of The Church of Jesus Christ of Latter-day Saints.
• noun obsolete, slang A person who is plucked, i.e. refused an academic degree.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun any important early teacher of Christianity or a Christian missionary to a people
• noun (New Testament) one of the original 12 disciples chosen by Christ to preach his gospel
• noun an ardent early supporter of a cause or reform