Who are the bondholders?
Bondholders are people or, more likely, institutions which lend money to countries and major companies. They lend, generally, for a set period of time and receive a set rate of interest, or coupon, at regular intervals from the borrower.
The seniority of bondholders relates to the position they occupy in the event of a country or company in which they have invested running into trouble. Secured bondholders are at the top of the list because their lending is secured against some assets of the borrower. Below these come senior unsecured bondholders -- such as those currently in the spotlight in relation to the Irish banks.
After them come subordinated bondholders, sometimes referred to as junior bondholders. As the name suggests, holders of these bonds have rights that are subordinate to those of senior bondholders.