a letter, esp. a formal or didactic one; written communication.

( usually initial capital letter ) one of the apostolic letters in the New Testament.

( often initial capital letter ) an extract, usually from one of the Epistles of the New Testament, forming part of the Eucharistic service in certain churches.

noun

billet doux , cannonball , card , communication , dispatch , fyi , get-well , invite , kite * , line * , love letter , memo , message , missive , note , poison pen , postcard , scratch * , tab * , thank-you , composition , letter