principal

principal — adjective

1. The most important, or the one that matters more than all others in a particular

1.adjectiveB1
Definition

The most important, or the one that matters more than all others in a particular situation.

Example

The principal reason for the meeting was to discuss the school's new building plans.

collocation: principal reason

Good health was the principal goal of Lakshmi's new exercise routine.

collocation: principal goal / principal objective

Common collocations
  • principal reason
  • principal goal
  • principal concern
  • principal objective
  • principal advantage
  • principal cause
Synonyms
  • main

    more common in everyday speech; 'main' can feel more direct while 'principal' is slightly more formal

  • primary

    emphasises first in order or sequence rather than just importance

  • chief

    similar meaning but more formal and less common in everyday use

Antonyms
  • minor

    less important or smaller in scale

  • secondary

    coming after the most important thing in order or importance

Grammar Patterns

principal + noun

Common Mistakes

Principle reason for the delay was the weather.
Principal reason for the delay was the weather.
'principal' is an adjective meaning 'most important'; 'principle' is a noun meaning 'a rule or belief'.

principal — noun

Word family

  • principally
    adverbB2
  • principle
    nounB2
  • principled
    adjectiveC1
  • unprincipled
    adjectiveC1

Synonym discussion

Sense: adjective/1

Principal, main, primary, and chief all describe something of high importance, but they differ in emphasis and context. Main is the most common and neutral word in everyday English — you talk about 'the main road', 'the main course of a meal', or 'the main idea of a paragraph'. Principal is slightly more formal and suggests the thing that matters most within a structured set of options, such as 'the principal reason', 'the principal concern', or 'the principal objective'. Primary emphasises first in time or order, not just importance — 'the primary purpose' or 'the primary colour' is the first or foundational one. Chief is the most formal of the four and often carries a sense of leadership or authority, such as 'the chief executive' or 'the chief cause'. For a learner: use main in speech, principal in writing, primary when listing priorities, and chief when referring to someone in charge.

principal ↗main ↗primary ↗chief ↗

Common collocations

Nouns

Verbs

Phrases

  • principal of a school
  • principal of a college
  • principal amount
  • principal balance
  • principal and interest
  • principal reason for

Adjectives

Etymology

LatinFrenchEnglish

The word 'principal' comes from Latin 'principalis', meaning 'first in importance'. This was formed from 'princeps' (princeps, princip-), meaning 'chief' or 'ruler', which is a combination of 'primus' (first) and 'capere' (to take). The meaning has stayed remarkably consistent — from 13th-century French 'principal' through to modern English, it has always referred to the most important person or thing in a group.