There are various other terms often used interchangeably with the phrase "biblical letter." One such alternative is "epistle," which refers to a letter written by an author of the New Testament, such as Paul's letters to various churches. Another synonymous term is "missive," which can refer to either a general term for any written message or specifically to a formal letter. Similarly, "missive literature" can refer to any collection of written messages or specifically to letters of theological content. Lastly, "correspondence" can be used to include both private letters and epistles, whereas "canonical letter" can refer to any of the New Testament letters considered part of the recognized biblical canon.