Salaam! Okk... A debenture is a long-term loan certificate issued by limited companies that can raise large sums of money for upto 25 years. It must be repaid along with interest. It's like an I-owe-you certificate. The business who needs the money gives this certificate which has the date of repayment on it to the other business,organisation,etc. In return, the lending organisation gives you money!! Its like my guarantee to them that I'll give the money back at sum point in the future. ( By the way, dont explain it this way in the exam. Use "sophisticated" business terms.... )