What is acknowledgement?

The act of acknowledging something.  In legal documents, for example, acknowledgement is given by a public officer.

In New York, an acknowledgment is defined as "executed in the manner required for a deed to be recorded", the same as a conveyance of title to real property. The acceptable language is:

Before me, the undersigned authority, personally appeared .........., who produced .................. as identification, and who acknowledged before me that they executed the foregoing instrument as their voluntary act and deed. In Witness Whereof, I have hereunto set my hand and seal this ........ day of ..................

Part of the content taken from: http://en.wikipedia.org/wiki/Acknowledgment_(law)