a symbol, usu written or printed, representing a speech sound and constituting a unit of an alphabet
a written or printed message addressed to a person or organization and usu sent through the post
Nobody knows how to write letters, and yet one has ’em, one does not know why. They serve one to pin up one's hair — Congreve
(in pl, but treated as sing. or pl)
literature
learning, esp scholarly knowledge of or achievement in literature
a man of letters
(the letter) the precise wording; the strict or literal meaning
the letter of the law
in printing, a style of type
to the letter
precisely or literally
obeyed the instructions to the letter
[Middle English via Old French from Latin littera letter of the alphabet, litterae (pl) epistle, literature]