1. Insurance: Special provisions added to an insurance policy to enhance or restrict its coverage. In other types of contracts also, endorsements are the addenda which, though not a part of the original, become its integral and legal part when attached. See also attachment and rider.
2. Trading: Signing a legal document in a legal capacity. Endorsement of any negotiable instrument (bill of exchange, bill of lading, delivery order, or other document of title) means the (1) endorser guarantees that he or she is the lawful owner of the instrument, (2) knows of no defect in it, (3) has received it in good faith for value received, and is (4) legally capable of transferring it to another party in the normal course of business. To endorse a promissory note as a third-party means the endorser guarantees payment in case the principal borrower defaults. To endorse a contract confirms approval of its contents and terms.