acknowledgment

Short definition from Wiktionary

Noun

1. 1
   The act of acknowledging
2. 2
   The act of recognizing in a particular character or relationship; recognition of existence, authority, truth, or genuineness.
3. 3
   A reward or other expression or token of gratitude.
4. 4
   An expression of gratitude for a benefit or an obligation.
5. 5
   A message from the addressee informing the originator that the originator's communication has been received and understood.
6. 6
   A response (ACK) sent by a receiver to indicate successful receipt of a transmission (See Wikipedia article on transmission).
7. 7
   A recognition as genuine or valid; an avowing or admission in legal form.
8. 8
   The act of a person admitting a child as their own.
9. 9
   A formal statement or document recognizing the fulfillment or execution of a legal requirement or procedure.