While you were in school, were you ever sent to the principal’s office? What about the principle’s office?
Principal – adjective – most important, consequential or influential
Principal – noun – a person in a role of authority, a person in a leading position especially at an educational institution
Principle – noun – a fundamental law, a rule of conduct, the ultimate source, origin or cause of something
Growing up my mom taught me this trick to remember the difference. The school principal and the principal ballerina are your pals, and if they are your pals, they must end in pal.
Do you have a grammar question? Let me know about it in the comments. I’ll answer your question in a future Grammar Tips post.