Junior Security 

A security with a claim on a corporation?s assets and income that is subordinate to that of a senior security. For example, common stock is junior to preferred stock, which is junior to unsecured debt such as debentures, which is junior to secured debt.

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.