Letter  —n. 1 character representing one or more of the sounds used in speech. 2 a written or printed message, usu. Sent in an envelope by post. B (in pl.) Addressed legal or formal document. 3 precise terms of a statement, the strict verbal interpretation (letter of the law). 4 (in pl.) A literature. B acquaintance with books, erudition. —v. 1 inscribe letters on. 2 classify with letters.  to the letter with adherence to every detail. [french from latin littera]