A certificate at the end of an affidavit.
A person administering an oath will check the identity of the affiant against that set out on the affidavit, and that the individual recognizes and fully accepts the entirety of the statements he or she makes within the affidavit, and witnesses or confirms the signature of the affiant upon the affidavit, adding detail such as the place and date of certification.
This is then confirmed and certified by the endorsement, the jurat, which set out the place and date of the oath given, followed by the signature of the officer and his or her printed name or, preferably, stamp of office in photographically reproducible form.
In John Bouvier's American Law Dictionary of 1856, he defined the term as:
"That part of an affidavit where the officer certifies that the same was "sworn" before him. The jurat is usually in the following form, namely 'Sworn and subscribed before me, on the ____ day of _______, 1842, (name and office).' In some cases it has been holden that it was essential that the officer should sign the jurat, and that it should contain his addition and official description."