1 : to indicate recognition and acceptance of [the power of taxation in the general and state governments is acknowledged to be concurrent "McCulloch v. Maryland , 17 U.S. 316 (1819)"]
2 a : to show by word or act that one has knowledge of and accepts responsibility for (a duty, obligation, or indebtedness)
b : to admit paternity of [will the child as his] compare filiate
3 : to make known to a sender or giver the receipt of (what has been sent or given) or the fact of (one's having received what has been sent or given) [ receipt of a letter]
4 : to recognize as genuine so as to give validity
: avow or admit in legal form [the execution of any such power of attorney shall be acknowledged before one of the officers "U.S. Code "]
Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.