A debenture is a type of debt instrument unsecured by collateral. Since debentures have no collateral backing, debentures must rely on the creditworthiness and reputation of the issuer for support. Both corporations and governments frequently issue debentures to raise capital or funds.
A mortgage bond is a bond secured by a mortgage or pool of mortgages. These bonds are typically backed by real estate holdings and real property such as equipment.
A serial bond is a bond issue that is structured so that a portion of the outstanding bonds mature at regular intervals until all of the bonds have matured.