A cosigned promissory note refers to a legal document where two parties agree to be equally responsible for the repayment of debt. There are a number of synonyms that can be used to describe this type of financial agreement, including a joint promissory note, shared loan contract, guaranteed loan document, and co-borrower agreement. Each of these phrases emphasizes the fact that two or more individuals are involved in the repayment of debt and that they have an equal stake in ensuring that the note is repaid on time and in full. Overall, a cosigned promissory note is an important legal instrument that allows people to provide financial support to one another in a structured and transparent way.