Principal vs. Principle: the Key Differences

English has many words that sound the same but have different meanings, which can sometimes be tricky. “Principal” and “principle” are examples of this.

At first glance, these two words might seem very similar. Their meanings and usage are quite different. The following information will help you learn when to use each word correctly.

Key Takeaways

  • Context Matters: Be mindful of the context to understand which word to use. “Principal” is tied to people in authority or primary importance, while “principle” is about rules or guidelines.
  • Grammar: “Principal” can be a noun or adjective; “principle” is only a noun.
  • Mnemonic Device: For “principle,” think of “rule” (both end in “le”). For “principal,” remember “pal” – your school’s principal.
  • By keeping these distinctions clear, you can use “principal” and “principle” correctly in your writing and speech.

Principal vs. Principle: Definition & Examples

Principal vs. Principle
Principal vs. Principle – Created by 7ESL

Definition of Principal

Principal can serve as both a noun and an adjective.

Principal as a noun:

As a noun, it often refers to a person who holds a leading or primary position. For example:

1. School Principal: The head of a school.

  • The principal greeted the students on the first day of school.

2. Principal in a Firm: A key figure or main investor.

  • He was the principal of a well-known law firm.

Principal as an adjective:

As an adjective, it describes something of highest importance or primary. For example:

1. Principal Reason: The most important reason.

  • The principal ingredient in this recipe is garlic.

2. Principal Investigator: The main researcher in a study.

  • Her principal concern was the safety of the children.

The word “principal” has roots in the Latin word “princeps,” meaning chief or leader. You can remember it by thinking of the principal of a school as your “pal.”

Definition of Principle

Principle is always a noun. It refers to fundamental truths, rules, or guidelines that shape actions, beliefs, and decisions. Principals are foundational understandings or moral rules. Examples of principles include:

1. Moral Principles: Beliefs about right and wrong.

  • Honesty is a key principle in maintaining trust.

2. Scientific Principles: Basic laws that explain natural phenomena.

  • The principles of physics explain how matter and energy interact.

The word “principle” stems from the Latin word “principium,” meaning beginning or foundation. A helpful mnemonic device is to focus on the ending “le” in “principle” which can remind you of “rule.”

Principal vs. Principle: Practice and Exercises

Fill in the blank 

  1. The __________ of the school addressed the students during the assembly.
  2. Honesty is an important __________ that she lives by.
  3. The __________ amount of the loan does not include the interest.
  4. The scientific __________ behind the experiment was sound.
  5. As the __________ actor, he had the most lines to memorize.
  6. The __________ of aerodynamics are crucial for aircraft design.
  7. She was awarded the __________ of the year for her outstanding leadership.
  8. The __________ reason for the company’s success is its customer service.
  9. He explained the basic __________ of the legal system to the jury.
  10. The __________ of the fund receives a higher percentage of the profits.

Answer with Explanation 

  1. Answer: principal
    • Explanation: “Principal” in this context refers to the head of a school.
  2. Answer: principle
    • Explanation: “Principle” refers to a fundamental truth or proposition that serves as the foundation for a system of belief or behavior.
  3. Answer: principal
    • Explanation: “Principal” here means the original sum of money lent or invested, excluding any interest or profit.
  4. Answer: principle
    • Explanation: “Principle” is used to describe a fundamental truth that serves as the base for a system of belief, in this case, scientific reasoning.
  5. Answer: principal
    • Explanation: “Principal” as an adjective means first in order of importance; the main actor.
  6. Answer: principles
    • Explanation: “Principles” are fundamental truths or propositions that serve as the foundation for a system, in this case, the science of aerodynamics.
  7. Answer: principal
    • Explanation: “Principal” in this context is used as a noun to describe the head of a school or organization.
  8. Answer: principal
    • Explanation: “Principal” as an adjective means the most important; the main reason.
  9. Answer: principles
    • Explanation: “Principles” refer to the fundamental truths or propositions that serve as the foundation for a system, in this case, the legal system.
  10. Answer: principal
    • Explanation: “Principal” here is used in a financial context to mean the person who has a primary position in a transaction, receiving a higher profit share.

Helpful Tips to Remember

Understanding the difference between “principal” and “principle” can be tricky. Here are some tips to help you remember:

  • Principal: Often refers to a person or primary entity. For example, the principal of a school or the main investment amount in finance.
  • Principle: Generally means a fundamental truth or rule. For example, a scientific principle or a moral principle.