There's more to it than “the principal is your pal.”
Today we’re going to recall that the principal is indeed your “pal,” but we’ll also see that a principal can be so much more. In this episode we’ll talk about the various ways to use “principle”—that’s “p-l-e”—and “principal”—that’s “p-a-l.” (These two words are pronounced the same way, principle, but I'm going to pronounce the one that ends with “pal” “princi-pal” so you can follow along more easily.)
A listener named Sarah has come across the word “principal” in relation to a job title and is wondering if that's the correct meaning. She asks, “If I am the partner that is responsible for and a technical contributor to our MySQL practice, will I be the principal (as I was taught over-simplistically in elementary school, the principal is your pal; it’s a noun) or the principle (a law or precept—again simplistic)? I don’t tend to think of myself as a law unto myself or the primary source, so spelling it ‘principle’ doesn’t seem right. And the definition of ‘principal’ of most important, consequential, or influential is closer, but I’ve gotten feedback from clients that each is wrong.”
It’s easy to confuse similar-sounding words like “principal” and “principle.” Let’s look at “principle” (ending in “p-l-e”) first. Sarah is right that it refers to a fundamental law, doctrine, or tenet (1). It is a noun only. You could use it to refer to grammatical principles, meaning rules, or you could say that someone is a man of principle, meaning a man who has strong ideals. As Sarah suspects, “principle” has nothing to do with a job title.
The word “principal” (ending in “p-a-l”), on the other hand, just might. Like Sarah, you’ve probably heard the trick that the head of a school is your pal. That is a good way to remember the spelling of “principal” because he or she is a fair disciplinarian and so is your pal, and because the head of a school is indeed spelled with “p-a-l” at the end. But the word means more than that.
“Principal” can be an adjective or a noun (2). The most common meaning of “principal” as an adjective is main, or highest in rank or importance, as in “My principal complaint is a persistent headache.”
You can also turn “principal” into the adverb “principally,” which means “for the most part.” You might see it in a sentence like this: “She was principally an abstract painter.”