principal

noun

1.
the original amount of a debt on which interest is calculated
2.
the educator who has executive authority for a school
Derived from:
principalship
3.
an actor who plays a principal role
4.
capital as contrasted with the income derived from it
5.
(criminal law) any person involved in a criminal offense, regardless of whether the person profits from such involvement
6.
the major party to a financial transaction at a stock exchange; buys and sells for their own account