principal
(the main person in in an organization or group, who can make important decisions)
- Let me consult my principal on this matter.
- He is the principal of the firm.
(main; first in order of importance)
- This country’s principal export is oil.
- A principal cause of roads accidents is drunk driving.
principle
(a moral rule or personal belief)
- It’s against my principles to tell a lie, even for my own advantage.
- As a matter of principle, he would not ask to borrow money.
(an idea or rule that something is based on)
- We would support the principles of democracy.
- The first principle of child-rearing is to choose a good mother.