ACK
1. /ak/ The {mnemonic} for the ACKnowledge
character, {ASCII} code 6.
2. A message transmitted to indicate that
some data has been received correctly. Typically, if the
sender does not receive the ACK message after some
predetermined time, or receives a {NAK}, the original data
will be sent again.
[{Jargon File}]
(1997-01-07)