ac·knowl·edge 
(ăk-nŏlĭj)
(ăk-nŏlĭj)tr.v. ac·knowl·edged, ac·knowl·edg·ing, ac·knowl·edg·es
1. To admit the existence or truth of: The doctors acknowledged that the treatment had not been successful.
2.
a. To express recognition of; make notice of: "When he saw me acknowledge him, he smiled as if we were dear friends" (Angela Patrinos).
b. To express gratitude or appreciation for or to: acknowledged the contributions of the volunteers; acknowledged her editor in the preface to the book.
3. To report the receipt of (something) to the sender or giver: acknowledge a letter.
4. Law To accept or certify as legally binding: acknowledge a deed of ownership.
[Probably blend of Middle English knowlechen, to acknowledge (from knouen, to know; see KNOW) and Middle English aknouen, to recognize (from Old English oncnāwan, to know : on-, on; see ON + cnāwan, to know; see KNOW).]
ac·knowledge·a·ble adj.
Synonyms: acknowledge, admit, own, confess, concede
These verbs express an acceptance of the reality or truth of something, especially something inconvenient, embarrassing, or detrimental to oneself. To acknowledge is to openly accept the truth of something that is usually already known or suspected: She acknowledged her mistake in a statement to the press.
Admit can suggest the acknowledgment of behavior or intentions that one knows to be wrong, embarrassing, or unseemly: He admitted under questioning that he had falsified his résumé.
Own or more commonly own up stresses acceptance of personal responsibility: "Recovering addicts ... say that when you are really in recovery, you want to own up to everything related to your drug use" (Michael Bamberger).
Confess often suggests disclosure of something that one is uncomfortable keeping to oneself: I have to confess that I lied to you.
To concede is to accept, often with reluctance or qualifications, what cannot reasonably be denied: "He conceded that he himself was not a great performer, but felt he had something that was even more important than acting ability" (Jeffrey Meyers).
These verbs express an acceptance of the reality or truth of something, especially something inconvenient, embarrassing, or detrimental to oneself. To acknowledge is to openly accept the truth of something that is usually already known or suspected: She acknowledged her mistake in a statement to the press.
Admit can suggest the acknowledgment of behavior or intentions that one knows to be wrong, embarrassing, or unseemly: He admitted under questioning that he had falsified his résumé.
Own or more commonly own up stresses acceptance of personal responsibility: "Recovering addicts ... say that when you are really in recovery, you want to own up to everything related to your drug use" (Michael Bamberger).
Confess often suggests disclosure of something that one is uncomfortable keeping to oneself: I have to confess that I lied to you.
To concede is to accept, often with reluctance or qualifications, what cannot reasonably be denied: "He conceded that he himself was not a great performer, but felt he had something that was even more important than acting ability" (Jeffrey Meyers).