BTU, or British thermal unit, is the industry-standard used to measure the heating efficiency of furnaces. In addition to BTU ratings, furnace manufacturers might include a Manual J Load rating and a percentage of energy efficiency.
A debenture is a type of debt instrument that is not secured by physical assets or collateral. Debentures are backed only by the general creditworthiness and reputation of the issuer. Both corporations and governments frequently issue this type of bond to secure capital.
A letter of credit is a liability for the bank because it is an obligation to pay out money. On the other hand, a bank bond is essentially an insurance product, so it counts as an asset: If everything goes smoothly, the bank keeps its fee and does not need to pay the bondholder.