noun

• (obsolete) A certificate of a loan made to the government; a government bond.
  "Madame Corre, who made the important decisions after her plodding husband had spent hours on the ledger, sold the family debentures and put the money into Dutch decurities."
• (finance, US) A type of debt instrument secured only by the general credit or promise to pay of the issuer, not involving any physical assets or collateral, now commonly issued by large, well established corporations with adequate credit ratings.
• (finance, UK) A document granting lenders a charge over a borrower’s physical assets, giving them a means to collect a debt, as part of a secured loan.
  "That the young Mr. Churchills liked—but they did not like him coming round of an evening and drinking weak whisky-and-water while he held forth on railway debentures and corporation loans. Mr. Barrett, however, by fawning and flattery, seemed to be able to make not only Mrs. Churchill but everyone else do what he desired."