A solemn declaration before another, complying with the laws of the state or country where made, that the document in which an applicant for patent declares that (1) he or she is the original or sole inventor, (2) shall state of what country he or she is a citizen, (3) that he or she has reviewed and understands the contents of the specification and claims which the declaration refers to, and (4) acknowledges the duty to disclose information that is material to patentability as defined by 37 CFR S 1.56. An oath or declaration must be filed in each nonprovisional patent application.

Source: U.S. Patent and Trademark Office.