- A transmission control character sent by a station indicating that it is not ready to receive a transmission. In ASCII, NAK is represented by the bit pattern 1010100. See also ASCII.
- A negative acknowledgement that a message, block, or frame has been received in errored condition across a communications circuit, and that it must be retransmitted. See also ACK, block, circuit, data set, frame, message, and station.
NAK - Computer Definition
(Negative AcKnowledgement) A communications code used to indicate that a message was received in error or that the endpoint is not ready to accept data or simply a "no" response to a query.