Compulsory Convertible Debenture - CCD
  
You gotta convert it. Think: The Inquisition...but for bonds.
The conversion nomenclature describing how and when and at what price and terms is all in the indenture, i.e. the fine print when the bond was issued. But the conversion? It's not optional like it is in most bonds. It is...compulsory. Like the first day of figure skating in the Olympics, where the skaters have to carve a perfect figure 8, or spin at just the right frequency. Otherwise, it's just a debenture: a low-end bond backed only by the handshake and promise of the company to pay. Which converts, usually into shares or stock or equity of the company that issued the security.