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").