Epistle

An epistle is a writing directed or sent to a person or group of persons, usually a letter and a very formal, often didactic and elegant one. The letters from Apostles to Christians in the New Testament are often referred to as epistles.

In the context of a liturgy, "epistle" may refer more specifically to a particular passage from a New Testament epistle that is scheduled to be read on a certain day or at a certain occasion.