noun
A literary composition in the form of a letter or series of letters, especially one in verse.
(chiefly literary or humorous) A letter, especially one which is formal or issued publicly.
One of the books of the New Testament which was originally a letter issued by an apostle to an individual or a community.
An extract from a New Testament epistle (noun, sense 3.1) or book other than a gospel which is read during a church service, chiefly the Eucharist.
verb
To write (something) in, or in the form of, a letter.
To write a letter to (someone).
To write (something) as an introduction or preface to a literary work; also, to provide (a literary work) with an introduction or preface.
To write a letter.
To communicate with someone through a letter.