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.
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; as, Dionysius of Corinth is called the apostle of France, John Eliot the apostle to the Indians, Theobald Mathew the apostle of temperance.
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.