Debentures are a type of loan that companies use to borrow money from investors. They function similarly to bonds but are considered part of the company's capital rather than debt. The document discusses the key differences between debentures and shares, including how debentures are presented on the balance sheet, the rights of debenture holders versus shareholders, and priority of payment. It also categorizes debentures based on security, redemption, negotiability, convertibility, priority, and interest rate. The accounting treatment of debentures issued as collateral security is explained.