1. A writing directed or sent to a person or persons; a written communication; a letter; -- applied usually to formal, didactic, or elegant letters.
A madman's epistles are no gospels. --Shak.
2. Eccl. One of the letters in the New Testament which were addressed to their Christian brethren by Apostles.
Epistle side, the right side of an altar or church to a person looking from the nave toward the chancel.
One sees the pulpit on the epistle side. --R. Browning.