A document in which an applicant for patent declares, under penalty of fine or imprisonment, or both (18 USC 1001), 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.
A sworn, written statement that is used as evidence in court. The statement supports or establishes a fact. The person that makes the declaration certifies or declares under penalty of perjury that the statement is true and correct. The person that makes the declaration is called the "declarant." The declarant must sign and date the declaration. The declaration must also say where the declaration was signed or that it was made under the laws of the State of California.
Source: California Courts.