Definition - What does Seal mean?
A seal is a distinguished marking, usually made from wax and a wooden stamp, which would be used to signify that a valid contract has been entered into. In early contract law, a seal was typically used in order to show that a contract was valid even though the contract entered into did not have any consideration.
Justipedia explains Seal
Under traditional common law, every contract that is entered into cannot be valid unless it contains consideration. In order for a contract to have consideration, there must be something of legal value that is being traded between the two parties. However, if a contract is sealed, it is presumed by the courts that consideration is there. The seal used in contract law is where the phrase "signed, sealed, and delivered" originates. Under the common law, a contract was automatically valid when it was signed, sealed, and delivered.