In
communications and
information processing,
code is a system of rules to convert
information—such as a
letter,
word, sound, image, or
gesture—into another form or representation, sometimes
shortened or
secret, for communication through a
channel or storage in a
medium. An early example is the invention of
language, which enabled a person, through
speech, to communicate what he or she saw, heard, felt, or thought to others. But speech limits the range of communication to the distance a voice can carry, and limits the audience to those present when the speech is uttered. The invention of
writing, which converted spoken language into
visual symbols, extended the range of communication across
space and
time.