Principal or principle? This is one of those questions that, even after 15 years as a professional writer, can still send me to my dictionary.
Speaking of which, here’s how American Heritage (fourth edition) sorts it out:
Principal and principle are often confused but have no meanings in common. Principle is only a noun and usually refers to a rule or standard. Principal is both a noun and an adjective. As a noun, it has specialized meanings in law and finance, but in general usage it refers to a person who holds a high position or plays an important role: a meeting among all the principals in the transaction. As an adjective it has the sense of “chief” or “leading”: The coach’s principal concern is the quarterback’s health.
Paul Brians has more, in case it’s still a little unclear:
Generations of teachers have tried to drill this one into students’ heads by reminding them, “The principal is your pal.” Many don’t seem convinced. “Principal” is a noun and adjective referring to someone or something which is highest in rank or importance. (In a loan, the principal is the more substantial part of the money, the interest is—or should be—the lesser.) “Principle” is only a noun and has to do with law or doctrine: “The workers fought hard for the principle of collective bargaining.”
So, if it’s a person you’re referring to, it’s principal. If it’s an adjective – no matter what – it’s principal. If it’s about significance or position, it’s…also principal. About the only time you’d use principle, then, is if it’s a basic law, truth, or assumption.
Something tells me I’ll still be reaching for my dictionary.
