ACK or Ack may refer to: Arts and entertainment Amar Chitra Katha, an Indian comic book series Technology Acknowledgement (data networks) ACK (TCP), the control character used in the Transmission Control Protocol to acknowledge receipt of a packet Amsterdam Compiler Kit, a retargetable compiler suite and toolchain Transportation Acklington railway station (Station code: ACK), a rail station in the UK Armstrong Whitworth F.K.8, an early aircraft known as the "Big Ack" Nantucket Airlines or ACK Air, an American airline Nantucket Memorial Airport (IATA: ACK, FAA LID: ACK), an airport in the US Other uses Assumption College, Kilmore, an Australian school Aka-Kora language (ISO 639-3: ack), an extinct Great Andamanese language TNK2 or ACK or ACK1, an enzyme that in humans is encoded by the TNK2 gene See also "Ack ack", from signalese for AA, referring to anti-aircraft artillery fire Andrew Haldane (1917–1944), an officer in the US Marine Corps in the Pacific Theatre, World War II nicknamed "Ack-Ack" Acknowledgment (disambiguation)