"Principal" Or "Principle"?
The words principle and principal are pronounced in the same way but they do not have the same meaning. Principle is normally used as a noun meaning ‘a fundamental basis of a system of thought or belief’, as in:
This is one of the basic principles of democracy.
one of the country’s principal cities
Principal can also be a noun, where it is used to refer to the most senior or most important person in an organization or other group, such as ‘the deputy principal’. It may also refer to a sum of money lent or invested, on which interest is paid, such as in 'the principal on the loan'.