Today’s Word Nerd came about after seeing a banner promoting a local concert series; somehow, these banners, several dozen of them, were designed, approved, printed and installed all over the city without anyone ever noticing the error they contain. If you look below Michael Feinstein’s name, you’ll see the words “Principle Conductor.” It should be “Principal.”
What’s the difference?
Principle: an accepted or professed rule of action or conduct; a fundamental law or truth from which others are derived; a fundamental doctrine or tenet; a distinctive ruling opinion.
Principal: first or highest in rank, importance, value, etc.; the head or director of a school; a person who takes a leading part in any activity, as a play; the first player of a division of instruments in an orchestra (excepting the leader of the first violins); something of primary or chief importance. In economics, a sum of money invested.
In other words, a principle is an idea and a principal is a person or thing of importance. The money you deposit into an account is the principal, and that amount grows because of the principle of compound interest.
Principle and principal originate from the same Latin root word, princeps, meaning first or chief, which then splits into two different meanings of first: principia (foundations) and principalis (most important); the two words came to Middle English around 1500.
If you say that Michael Feinstein is the Principle Conductor, you’re saying that he conducts principles.
If you say that Isaac Newton discovered the Principal of Gravity, you’re saying that he discovered the person responsible for making sure gravity operates correctly.