n An owning with gratitude of a benefit or an obligation (as in "acknowledgment" of a favor).
n A message from the addressee informing the originator that the originator's communication has been received and understood, as a wedding invitation's acknowledgment.
n (context|Telecommunications|computing|networking) A response (ACK) sent by a receiver to indicate successful receipt of a transmission.
n An owning as genuine or valid; an avowing or admission in legal form (as in "acknowledgment of a deed").
n (context|legal) A formal statement or document recognizing the fulfillment or execution of a legal requirement or procedure.