Error acknowledgment (3)
I believe the answer is:
sic
'error acknowledgment' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sic that I've seen before include "Thus, sounds ill" , "It calls attention to a quoted mistake" , "Urge to attack" , "(Of quoted word) exactly so" , "Thus among musicians" .)