Principle: a guiding rule or belief

The idea

Principle is countable: a principle, principles. In principle means generally or in theory; on principle means because of a firm belief.

Examples

• Fairness is a guiding principle for our team.
• The architect explained the principles of passive cooling.
• He refused the gift on principle.
• In principle, the plan could work, but we need more funding.
• Their decision was based on the principle of equal access.
• A good principle can be difficult to apply in practice.

Watch out

Do not confuse principle with principal, which can mean most important or the head of a school.

Try it yourself

1. Choose the correct word. Honesty is an important ___ in their work. (principle / principal)

   Show answer or example answer

   principle

   Principle names the belief that guides the work.

2. Choose the correct word. The scientist described three basic ___. (principle / principles)

   Show answer or example answer

   principles

   Principles is plural because there are three.

3. Choose the correct word. We agree in ___, but the details need discussion. (principle / principal)

   Show answer or example answer

   principle

   Principle completes the expression in principle, meaning agreement in general.

Use it today

Name a principle that guides a decision and explain how it applies.