(British) The act of acknowledging; admission; avowal; owning; confession.
(British) The act of owning or recognizing in a particular character or relationship; recognition as regards the existence, authority, truth, or genuineness.
(British) A message from the addressee informing the originator that the originator's communication has been received and understood.a wedding invitation's acknowledgement
(British, telecommunications, computing, networking) A response sent by a receiver to indicate successful receipt of a transmission.See Wikipedia article on transmission (telecommunications)
(British, legal) The act of a man admitting a child as his own.
(British, legal) A formal statement or document recognizing the fulfilment or execution of a legal requirement or procedure.