Definition of: epistle

(i·pis′əl) noun
1. A written message; communication; letter: more formal than letter, and especially applied to ancient epistolary writings of sacred character or of literary excellence: the Pauline epistles.
2. Eccl. Usually cap. A selection, usually from an apostolic epistle, read in the communion service of the Greek, Roman, and Anglican churches. [OE epistol <L epistola <Gk. epistolē <epi- on + stellein send]