Principal can mean the head of a school. It can also mean the most important person or thing, or the original amount of money in a loan.
- The principal welcomed the students.
- The principal reason was cost.
- She repaid the loan principal.
A principle is a rule, belief or basic idea.
- Honesty is an important principle.
- He refused to compromise his principles.
- The system works according to a simple principle.
Easy way to remember
The principal is your pal at school.
Principal = person/main thing
Principle = rule or belief