In TCP, what does the acronym 'ACK' stand for?

In the context of TCP (Transmission Control Protocol), the acronym 'ACK' stands for Acknowledgement. This term is crucial within the TCP protocol because it indicates that a segment of data sent from one host to another has been received successfully. When a sender transmits data, the receiver sends back an ACK packet to confirm receipt of that data. This acknowledgment process is fundamental to TCP’s reliability; it helps ensure that the data sent across the network is accurate and complete.

In scenarios where packets are lost during transmission, the lack of an ACK can trigger the sender to retransmit the data, ensuring that the communication is maintained without loss. This mechanism allows TCP to provide a connection-oriented communication service that is robust against errors and streamlines data transfer. Thus, the understanding of ACK in TCP is vital for anyone studying network protocols and security in computing.