1. /ak/ The mNemoNic for the ACKNowledge character, ASCII code 6. 2. NicatioNs> 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)