Principle versus Principal

When should you use principle and principal? Principle and principal are homophones, meaning that they are pronounced the same, but are spelled differently and have different meanings.

principle versus principal

Both words are commonly used as nouns, but only one of them has the added use as an adjective.

  • Principle is a general law or fundamental concept.
  • Principal, as a noun, is the head of a school or a leader, and as an adjective, means the first or most important.

Let’s examine these two words more closely.

When to Use Principle in a Sentence

Principle meaning: Principle is used as a noun to refer to a fundamental idea or concept, a guiding law or general truth.

Example: “Khalilzad said last Monday that the agreement ‘in principle’ to begin a U.S. troop withdrawal only needed Trump’s approval.” [noun] Source: Chicago Sun-Times

Example: The basic principle of Mothers Against Drunk Driving is to prevent impaired driving. [noun]

Example: “In the United Kingdom, care ‘free at the point of service’ was a founding principle of the National Health Service when it was established after World War II.” [noun] Source: LA Times

A principle can be thought of as a rule or guideline that should be followed.

Phrases that Use Principle

A matter of principle: A situation in which it is required that something be done a specific way because one believes that it is the only right way.

  • The judge had to disqualify her as a matter of principle.

A man of principle: A person who holds himself to a high personal moral code of conduct.

  • Everyone considered him to be a man of principle, so we were all shocked when he was arrested for embezzlement.

When to Use Principal in a Sentence

Principal meaning: Principal can be used as a noun or an adjective. As a noun, it means the leader/person with the highest level of authority, most commonly, the leader of a school. In the world of finance, principal is a noun that refers to the original amount of a loan. As an adjective, principal describes the first or most important person or item.

Example: “Pondiscio reports teachers and principals pressuring them to withdraw children who have behavior problems.” [noun] Source: New York Times

Example: “As monthly mortgage payments are made, the loan principal is reduced.” [noun]

Example: “Mr. Mazzola, who is currently the principal guest conductor at the Deutsche Opera in Berlin, was until recently artistic and music director of Orchestre National d’Ile-de-France in Paris.” [adjective] Source: New York Times

Word Origin: Principle versus Principal

The word principal is older than principle by about a century. Both words originated in Middle English and were influenced by Latin, which was common of the time. Principal emerged around the year 1250 as an English adaptation of the Latin principalis, meaning first. It comes from the same root word as prince.

Principle came to Middle English via Middle French and Latin around the year 1350. It was developed from the word principe, or prince, and was term coined to be a counterpart to the word, manciple. While manciple referred to the beliefs of the common soldier, principle was the loftier beliefs of the prince.

Principle or Principal? How to Know Which One to Use

In many cases, both principle and principal are nouns, so it is understandable that people often use the wrong version of the word. Here is a trick to keeping them straight.

If you are referring to a school leader or primary person, remind yourself that “The principal is our pal.”

If you are using the word as an adjective, you need to use principal. Look at your sentence. Is there a noun immediately following principal that the word is describing? If there is, then you need to use principal, not principle.

Test Your Knowledge:

Now it is your turn. Remember to apply to the above tricks to help you to know whether to use principle or principal.

  • Jonathan practiced hard to become the ____________ trombonist with the symphony.
  • What is the guiding _____________ of the First Amendment?
  • Daniels is currently the director of student affairs, but she hopes to one day become the ____________.

Answers listed below.

Recap: When to Use Principle or Principal

Principle and Principal may sound the same when we say them out loud, but they are two different words, each with their own spelling and own definition.

  • A principle is a doctrine or guiding belief.
  • A principal is either a person in a leadership role, particularly in academia, or an adjective to denote the most significant or first.


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