acknowledgment, in law, formal declaration or admission by a person who executed an instrument (e.g., a will or a deed) that the instrument is his. The acknowledgment is made before a court, a notary public, or any other authorized person. Acknowledgment permits the instrument to be given in evidence without any further proof of its execution (e.g., witnesses).
Acknowledgment (electronic tax filing), an official electronic notice from the IRS or a state tax authority indicating whether or not the e-file was accepted and considered “filed” or rejected and considered “not filed.”
Acknowledgment (social), a written thank you note expressing gratitude for gifts, assistance, or expressions of sympathy
Acknowledgement - ethical, as in to "offer someone acknowledgement" or to "provide recognition". To take someone seriously as an end in themselves, as a human worthy of respect, as having a valid point of view, as a genuine ethical subject.