Grammar for Geeks: Principle vs. Principal

Principle and Principal are often confused because all those years in school where you used one almost exclusive to the other. The difference is that principal means primary. In school, the pricipal was the person in charge. Some small businesses refer to their founders/owners as principals. Principal is also used in financial contexts to refer to the initial value of an investment which is differentiated from its interest or profit. For example, if you put $100 into a bank account and earned $10 of interest, the $100 would be called the principal.

Principle on the other hand means belief. This is typically used in discussions where someone might say "it's the principle of it" to argue why he cares about something.

The rule is simple:

Use 'principal' when you're referring to a person or an amount of money.
Use 'principle' when you're referring to an idea.

Word	Example
principal	My high school principal was a real jerk.
principle	I refuse spend a nickle in Lousiana because it violates my long standing principle of not giving money to people that reject science.

Last updated: Sun Mar 1 12:58:49 PST 2009