To admit the knowledge of; to recognize as a fact or truth; to declare one's belief in

"to acknowledge the being of a god"

To own or recognize in a particular quality, character or relationship; to admit the claims or authority of; to give recognition to.

To be grateful of (e.g. a benefit or a favour)

"to acknowledge a favor"

To report (the receipt of a message to its sender).

"This is to acknowledge your kind invitation to participate in the upcoming debate."

To own as genuine or valid; to assent to (a legal instrument) to give it validity; to avow or admit in legal form.

The act of acknowledging something.

That acknowledges, in various sense; (especially) that notices or recognises someone or something.

(specifically) Expressing esteem or gratitude.