idea

American  

[ahy-dee-uh, ahy-deeuh] / aɪˈdi ə, aɪˈdiə /

noun

1. any conception existing in the mind as a result of mental understanding, awareness, or activity.

2. a thought, conception, or notion.

   That is an excellent idea.

3. an impression.

   He gave me a general idea of how he plans to run the department.

4. an opinion, view, or belief.

   His ideas on raising children are certainly strange.

   Synonyms:

   judgment, sentiment

5. a plan of action; an intention.

   the idea of becoming an engineer.

6. a groundless supposition; fantasy.

7. Philosophy.

   1. a concept developed by the mind.

   2. a conception of what is desirable or ought to be; ideal.

   3. Also called form.  (initial capital letter) an archetype or pattern of which the individual objects in any natural class are imperfect copies and from which they derive their being.

   4. Kantianism. idea of pure reason.

8. Music. a theme, phrase, or figure.

9. Obsolete.

   1. a likeness.

   2. a mental image.

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idea ¹ British  

/ aɪˈdɪə /

noun

1. any content of the mind, esp the conscious mind

2. the thought of something

   the very idea appals me

3. a mental representation of something

   she's got a good idea of the layout of the factory

4. the characterization of something in general terms; concept

   the idea of a square circle is self-contradictory

5. an individual's conception of something

   his idea of honesty is not the same as yours and mine

6. the belief that something is the case

   he has the idea that what he's doing is right

7. a scheme, intention, plan, etc

   here's my idea for the sales campaign

8. a vague notion or indication; inkling

   he had no idea of what life would be like in Africa

9. significance or purpose

   the idea of the game is to discover the murderer

10. philosophy

    1. a private mental object, regarded as the immediate object of thought or perception

    2. a Platonic Idea or Form

11. music a thematic phrase or figure; motif

12. obsolete a mental image

13. to become ambitious, restless, etc

14. not what one regards as (hard work, a holiday, etc)

15. that is worth considering

16. that is preposterous, unreasonable, etc

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Idea ² British  

/ aɪˈdɪə /

noun

1. another name for Form

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idea Idioms  

1. see bright idea; put ideas in someone's head; what's the idea.

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Usage

What are other ways to say idea? An idea is any conception existing in the mind as a result of mental understanding, awareness, or activity. How is idea different from thought, conception, and notion? Learn more on Thesaurus.com. 

Other Word Forms

• idealess adjective
• preidea noun
• subidea noun

Etymology

Origin of idea

First recorded in 1400–50; from Late Latin from Greek idéā “form, pattern,” equivalent to ide- (stem of ideîn “to see”) + -ā feminine noun ending; replacing late Middle English idee from Middle French from Late Latin, as above; akin to wit ¹

Example Sentences

This article about building wealth is based on a simple idea, and you should read and share it even if you have already taken Beth’s advice.

From MarketWatch • Apr. 10, 2026

In its primordial form, liberalism was a political belief that the building block of society is the individual—an idea tethered loosely to the Christian notion that every single human being contains a divine spark.

From The Wall Street Journal • Apr. 10, 2026

Future observations will be crucial for testing this idea.

From Science Daily • Apr. 10, 2026

As the class started and the instructor dimmed the lights to an orange glow, it hit me that hot yoga might be a horrible first date idea.

From Los Angeles Times • Apr. 10, 2026

Humans, of course, had no idea they had such influence.

From "The Undead Fox of Deadwood Forest" by Aubrey Hartman

Related Words

• belief
• concept
• conception
• conclusion
• design
• feeling
• form
• intention
• interpretation
• meaning
• notion
• objective
• opinion
• perception
• plan
• scheme
• sense
• solution
• suggestion
• theory