Winning Words of the Scripps Spelling Bee Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Word Origin and History for ack

British oral code for letter A in wireless and telephone communication, 1898; hence ack-ack "anti-aircraft" (gun, fire, etc.).

Online Etymology Dictionary, © 2010 Douglas Harper
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ack in Technology

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]

The Free On-line Dictionary of Computing, © Denis Howe 2010
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Related Abbreviations for ack


  1. acknowledgment
  2. Nantucket Memorial Airport


  1. acknowledge
  2. acknowledgment
The American Heritage® Abbreviations Dictionary, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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