Caveat and Caveat Emptor

in law, a notice served on a public officer or court to refrain from doing a certain act without first giving notice to the caveator, as the person is termed who enters the caveat. Perhaps the best known use of the caveat in the United States is its entry by an inventor in the Patent Office for the purpose of establishing his claim to priority of invention, by enjoining its officers from issuing letters patent for any invention interfering with or infringing the rights claimed by the caveator without first giving him notice of the application for such letters patent.