ACK /ak/ interj. 1. [common; from the ASCII mnemonic for 0000110]
   Acknowledge. Used to register one's presence (compare mainstream _Yo!_).
   An appropriate response to ping or ENQ. 2. [from the comic strip
   "Bloom County"] An exclamation of surprised disgust, esp. in "Ack
   pffft!" Semi-humorous. Generally this sense is not spelled in caps (ACK)
   and is distinguished by a following exclamation point. 3. Used to
   politely interrupt someone to tell them you understand their point (see
   NAK). Thus, for example, you might cut off an overly long explanation
   with "Ack. Ack. Ack. I get it now". 4. An affirmative. "Think we ought
   to ditch that damn NT server for a Linux box?" "ACK!"

   There is also a usage "ACK?" (from sense 1) meaning "Are you there?",
   often used in email when earlier mail has produced no reply, or during a
   lull in talk mode to see if the person has gone away (the standard
   humorous response is of course NAK (sense 1), i.e., "I'm not here").

	

	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)