ETYM Old Eng. epistle, epistel, AS. epistol, pistol, Latin epistola; cf. Old Fren. epistle, epistre, French épître. Related to Stall.
Especially a long, formal letter.
In the New Testament, any of the 21 letters to individuals or to the members of various churches written by Christian leaders, including the 13 written by St Paul. The term also describes a letter with a suggestion of pomposity and literary affectation, and a letter addressed to someone in the form of a poem, as in the epistles of Horace and Alexander Pope.
The epistolary novel, a story told as a series of (fictitious) letters, was popularized by Samuel Richardson in the 18th century.

1. A communication (usually brief) that is written or spoken or signaled
2. What a communication that is about something is about; SYN. content, subject matter, substance.

ETYM French lettre missive. Related to Mission.
A letter; a written communication of any sort sent to the one to whom it is addressed.