Acknowledgment: A formal declaration before an authorized official, such as a notary public, by someone who signs a document and confirms that the signature is authentic. Also, the certificate of the officer on such instrument indicating that the document has been so acknowledged.
Affidavit: A voluntary declaration of facts, written down and sworn to or affirmed by the declarant (“affiant”) before a Notary Public or other officer having the authority to administer an oath.
Affirmation: The act of affirming the truth of a document, not an oath. "I solemnly affirm and declare the foregoing to be a true statement...” Note that an affidavit may appear in two forms: an affidavit with oath, or an affirmed affidavit with affirmation. Each has the same legal import.
Jurat: A certification added to an affidavit or document stating when, where and before whom such affidavit was made.
Oath: A solemn declaration, accompanied by a swearing to God or a revered person or thing, that one’s statement is true or that one will be bound to a promise. The person making the oath implicitly invites punishment if the statement is untrue or the promise is broken.
Protest: A Notary Public’s written statement that, upon presentment for payment or acceptance, a negotiable instrument was neither paid nor accepted.
Verification: A formal declaration by which one swears to or affirms the truth of the statements in a document. Also, the statement of a Notary Public that the person appearing before the notary has been properly identified as being the person purported to be appearing.