A provision in a contract or in a testamentary or other legal document that, upon the occurrence of specific events, a party's future interest in certain property will prematurely vest. For example, in many loan or mortgage agreements, provision is made that if some specified event occurs, such as the debtor's failure to pay an installment, the creditor may declare the entire outstanding balance to be immediately due. acceptance 1n.The act of voluntarily agreeing, expressly or by implication,...