Junk Bond 

A debt obligation with a rating of Ba or BB or lower, generally paying interest above the return on more highly rated bonds, sometimes known as high-yield bonds.

Remarks: Bond funds including mutual funds (open-end and closed-end, actively managed and indexed), exchange-traded funds and unit investment trusts offer a convenient and affordable way to invest in a diversified portfolio of bonds, but a bond fund investment can differ from a bond investment in ways that are important to understand.