Principal (music)
WordNet
noun
(1) The major party to a financial transaction at a stock exchange; buys and sells for his own account
(2) The educator who has executive authority for a school
"She sent unruly pupils to see the principal"
(3) An actor who plays a principal role
(4) Capital as contrasted with the income derived from it
(5) The original amount of a debt on which interest is calculated