# Principal vs. Principle | Definition & Examples

Published on August 8, 2022 by [Eoghan Ryan](https://www.scribbr.com/author/eoghanr/). Revised on March 11, 2023.

**Principle** and **principal** are pronounced the same but have different meanings.

- **Principal** can be used as a [noun](https://www.scribbr.com/category/nouns-and-pronouns/) to refer to a person in authority, the perpetrator of a crime, or the capital sum of a loan. It can also be used as an [adjective](https://www.scribbr.com/parts-of-speech/adjectives/) to mean “most important” or “primary.”

- **Principle** is a noun used to refer to a scientific, moral, or legal rule or standard.

| Examples: Principal in a sentence | Examples: Principle in a sentence |
| --- | --- |
| The **principal** of the school is very strict when it comes to attendance. | Chris refused to pay the extra shipping costs on **principle**. |
| The **principal** finding of the study is questionable. | Isaac Newton uncovered the **principles** of gravity and motion. |

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## Table of contents

1. [Principal as a noun](https://www.scribbr.com/commonly-confused-words/principal-vs-principle/#noun)
2. [Principal as an adjective](https://www.scribbr.com/commonly-confused-words/principal-vs-principle/#adjective)
3. [Principle is a noun](https://www.scribbr.com/commonly-confused-words/principal-vs-principle/#principle-noun)
4. [In principle or in principal](https://www.scribbr.com/commonly-confused-words/principal-vs-principle/#in-principle)
5. [Worksheet: Principal vs. principle](https://www.scribbr.com/commonly-confused-words/principal-vs-principle/#worksheet)
6. [Other interesting language articles](https://www.scribbr.com/commonly-confused-words/principal-vs-principle/#other)

## Principal as a noun

**Principal** can be used as a noun to refer to a person in authority, especially in a school but also in other contexts such as businesses.

Examples: Principal to mean person in authority

After twenty years of being a teacher, Kelly became the school **principal**.

It can also refer to someone who is responsible for a crime.

Example: Principal to refer to a perpetrator of a crime

There was no evidence to suggest that the young man was a **principal** in the robbery.

**Principal** can also be used in financial contexts to refer to the capital sum of a loan.

**Example: Principal to refer to a loan**

Melissa was happy with the principal, but she wished the interest rate weren’t so high.

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## Principal as an adjective

**Principal** can be used as an adjective to mean “primary” or “most important.” It can also be used to refer to an original sum of money.

Examples: Principal as an adjective

The **principal** aim of the mission was to test Saturn’s atmosphere.

The **principal** amount was two thousand dollars.

## Principle is a noun

**Principle** is a noun used to refer to a legal, natural, or scientific rule or standard. It can also be used to refer to a general or personal moral standard.

Examples: **Principle in a sentence**

The **principle** of human rights is central to the idea of democracy.

As a matter of **principle**, the politician refused to accept campaign funding from big businesses.

**Principle** can only ever be used as a noun (the associated adjective is “principled,” meaning “based on principle”).

## In principle or in principal

**In principle** is a common expression meaning “in theory.” It’s used to refer to a plan or idea, the details of which have not been established. “In principal” is never correct.

Examples: **In principle in a sentence**

Anna’s supervisor agreed **in principle** to the thesis topic, but they wanted to see a detailed plan before they officially agreed.

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## Worksheet: Principal vs. principle

You can test your understanding of the difference between “principle” and “principal” with the worksheet below. Fill in either “principle” or “principal” in each sentence.

- [Practice questions](https://www.scribbr.com/commonly-confused-words/principal-vs-principle/#)
- [Answers and explanations](https://www.scribbr.com/commonly-confused-words/principal-vs-principle/#)

1. As he was responsible for the damage to the car, Hector said that he would pay for it out of _________.
2. Because Dan was misbehaving, the teacher sent him to see the _________.
3. Each week, June saved her wages and paid off a part of the _________.
4. The _________ cause of the accident was that someone had spilled water on the floor.
5. In _________, the investor agreed with the business idea.

1. As he was responsible for the damage to the car, Hector said that he would pay for it out of **principle**.
   - “Principle” is a noun used to refer to a rule or standard. In this instance, “principle” is used to refer to a personal standard.

2. Because Dan was misbehaving, the teacher sent him to see the **principal**.
   - “Principal” can be used as a noun to refer to a person of authority in a school or business.

3. Each week, June saved her wages and paid off a part of the **principal**.
   - “Principal” is used here to refer to the capital sum of a loan.

4. The **principal** cause of the accident was that someone had spilled water on the floor.
   - “Principal” can be used as an adjective to mean “primary” or “most important.”

5. In principle, the investor agreed with the business idea.
   - Here, “principle” is used to complete the expression “in principle,” meaning “in theory.”

## Other interesting language articles

If you want to know more about [commonly confused words](https://www.scribbr.com/category/commonly-confused-words/), [definitions](https://www.scribbr.com/category/definitions/), and differences between [US and UK spellings](https://www.scribbr.com/category/us-vs-uk/), make sure to check out some of our other language articles with explanations, examples, and quizzes.

**Confused words**

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- [Affect vs effect](https://www.scribbr.com/commonly-confused-words/affect-vs-effect/)
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**Definitions**

- [Albeit](https://www.scribbr.com/definitions/albeit/)
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- [Mea culpa](https://www.scribbr.com/definitions/mea-culpa/)
- [Presumptuous](https://www.scribbr.com/definitions/presumptuous/)

**US vs. UK spellings**

- [Burned or burnt](https://www.scribbr.com/us-vs-uk/burned-or-burnt/)
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- [Dreamt or dreamed](https://www.scribbr.com/us-vs-uk/dreamt-or-dreamed/)
- [Gray or grey](https://www.scribbr.com/us-vs-uk/gray-or-grey/)
- [Theater vs theatre](https://www.scribbr.com/us-vs-uk/theatre-vs-theater/)

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## [Eoghan Ryan](https://www.scribbr.com/author/eoghanr/)

Eoghan has a lot of experience with theses and dissertations at bachelor's, MA, and PhD level. He has taught university English courses, helping students to improve their research and writing.