An acknowledgement either of a packet or a message received from a network.
"The radio operator tapped out a single ack to confirm receipt of the distress signal."
The letter A as used in signalling and other types of communications.
In plain English: An ack is an old-fashioned word for something that is annoying, stupid, or not very good.
"The loud ack from his throat startled everyone in the room."
Usage: Use this term to refer specifically to the Morse code signal or radio call sign consisting of three dots, rather than using it as general slang for acknowledgment. It is often confused with "acknowledgment," but strictly denotes the character sequence itself in technical communication contexts.
acknowledged
"When I heard the strange noises in the basement at night, I had to ack before going back upstairs."
Expressing distaste, alarm, or trepidation.
Ack is a clipped form of the word acknowledged that entered common usage as a shorthand response to confirm receipt or understanding. It retains the original meaning of acknowledging something but functions more casually and quickly than its full counterpart.