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

Explanation

When you suddenly know what to do and a cartoon light bulb appears above your head, you've probably just had an idea. After burning the roast and dropping the mashed potatoes, ordering pizza seemed like your best idea all night. Idea goes all the way back to idein in Greek, meaning “to see.” When someone says “Picture this!” they want to give you an idea. When you try to imagine something, idea can also mean a rough outline or a general sense: "This drawing I've made doesn't show every detail of my time machine, but it will give you some idea of how it works."

Example Sentences

I also like the idea of creating a permanence in the playfulness.

From Los Angeles Times • Apr. 13, 2026

Generally, it’s a smart idea not to overshare finances, social engagements, vacation plans, and so on.

From MarketWatch • Apr. 13, 2026

“Churchill railed against the idea that any event was unavoidable,” Mr. Vinen writes.

From The Wall Street Journal • Apr. 13, 2026

The idea of giant atoms was first introduced by researchers at Chalmers over a decade ago and is now widely used in the field.

From Science Daily • Apr. 13, 2026

Maybe Ma meant well, but the whole idea struck me as disturbing.

From "The Red Car to Hollywood" by Jennie Liu

Related Words

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