Affidavit

A sworn statement written down and made under oath before a notary public or other official authorized by law to administer an oath. The term literally means “has pledged one’s faith.” The affiant (person making the oath, sometimes called the “deponent”) must swear before the notary that the facts contained in the affidavit are true and correct. An affidavit is a complete instrument within itself, whereas an acknowledgment is always part of, or an appendage to, another instrument. An affidavit is sworn to, but an acknowledgment is not. 

The purpose of an affidavit is to help establish or prove a fact, such as identity, age, residence, marital status, and occupancy of property.