Cambridge Dictionaries online Cambridge Dictionaries online

The most popular online dictionary and thesaurus for learners of English

Principal or principle?

from English Grammar Today

Principal as an adjective means ‘most important’:

The principal reason for the failure to take action was poor communication between government departments. (the most important reason)

We can use principal as a noun to mean the head of a school or college (especially in American English):

The college principal made a speech congratulating all the students who were graduating in that year.

Principle is a noun. It means ‘a rule or theory which explains how something is or works’ or ‘a moral rule or guideline’:

The scientific principles behind even the most complicated computer are relatively simple.

He seems to have no principles at all, and is only interested in money. (He has no moral rules or guidelines.)

(“Principal or principle ?” from English Grammar Today © Cambridge University Press. Need grammar practice? Try English Grammar Today with Workbook.)
Add Cambridge dictionaries to your browser to your website

Word of the Day

improvisation

a performance that an actor, musician, etc. has not practised or planned

Word of the Day

Blog

Read our blog about how the English language behaves.

Learn More

New Words

Find words and meanings that have just started to be used in English, and let us know what you think of them.

Learn More