Principal vs. Principle

"Principal" and "principle" are two words that are easy to confuse. They sound the same, but they have very different meanings. This guide will break down the difference and give you a simple trick to get it right every time.

The Basic Rule: A Person vs. an Idea

Here's the one thing you need to remember:

• Principal is a person or the main thing.
• Principle is a rule or a belief.

Principal: A Person or the Main Thing

Principal can be a noun or an adjective.

As a Noun (a person)

This is the one you probably remember from school. The principal is the person in charge of a school.

• Example: "The principal gave a speech at the assembly."

It can also refer to the main person in other situations.

• Example: "She is the principal dancer in the ballet company."

As an Adjective (the main thing)

As an adjective, principal means "main" or "most important."

• Example: "The principal reason for our success is teamwork."
• Example: "Our principal concern is customer satisfaction."

In Finance

In finance, the principal is the original amount of a loan.

• Example: "You have to pay interest on the principal of the loan."

A Simple Memory Trick

Your principal is your pal.

Principle: A Rule or a Belief

Principle is always a noun. It's a fundamental truth, a rule, or a belief.

Examples of "Principle"

• He is a man of high principles. (He has strong moral beliefs.)
• The principle of supply and demand is a key concept in economics. (It's a fundamental rule.)
• I agree with you in principle, but I'm not sure it will work in practice. (I agree with the basic idea.)
• The machine works on the principle of magnetic attraction. (It's a fundamental truth.)

A Simple Memory Trick

"Principle" and "rule" both end in "-le."

A Quick Test

1. Are you talking about a person or the main thing? → Use principal.
2. Are you talking about a rule or a belief? → Use principle.

Test Yourself

Choose the right word:

1. The (principal/principle) of the school is new this year.
2. It's against my (principals/principles) to lie.
3. The (principal/principle) reason for the delay was the weather.
4. He has strong moral (principals/principles).
5. The (principal/principle) of the loan is $10,000.
6. She is the (principal/principle) investigator on the project.
7. I understand the basic (principals/principles) of physics.
8. Our (principal/principle) goal is to increase sales.
9. He refused to do it as a matter of (principal/principle).
10. The two (principal/principle) characters in the story are a detective and a thief.

Answer Key: 1. principal, 2. principles, 3. principal, 4. principles, 5. principal, 6. principal, 7. principles, 8. principal, 9. principle, 10. principal

Remember: Your principal is your pal, and a principle is a rule. Master this simple trick, and you'll never mix them up again!