Mistake (contract law) void. Traditionally, Caveat Emptor (let the buyer beware), and under Common Law Caveat Venditor (let the seller beware). A contract might be voidable from unilateral mistake for any of the following: A mutual mistake occurs when the parties to a contract are both mistaken about the same "material" fact within their contract. They are at cross-purposes. There is a meeting of the minds, but the parties are mistaken. Hence the contract is voidable. "Collateral" mistakes will not afford the right of rescission. A collateral mistake is one that 'does not go to the heart' of the contract. For a mutual
Patent caveat Patent caveat A patent caveat, often shortened to caveat, was a legal document filed with the United States Patent Office. Caveats were instituted by the U.S. Patent Act of 1836, but were discontinued in 1909, with the U.S. Congress abolishing the system formally in 1910. A caveat was similar to a patent application with a description of an invention and drawings, but without examination for patentable subject matter and without a requirement for patent claims. A patent caveat was an official notice of intention to file a patent application at a later date. A caveat expired after one year, but