Senior Notes

See: Senior Convertible Note.

When a note is Senior, it's first in the bond stack to be paid, should things go awry, and the company is unable to pay its debt obligations any more. Those notes come behind the IRS and vendor obligations and things like paychecks for the company's last remaining employees.

Senior notes would likely pay less interest than Junior notes, because at least notionally, they are of lower risk. And investors like lower risk.