Idea

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 1. Something, such as a thought or conception, that potentially or actually exists in the mind as a product of mental activity.
 2. An opinion, conviction, or principle: has some strange political ideas.
 3. A plan, scheme, or method.
 4. The gist of a specific situation; significance: The idea is to finish the project under budget.
 5. A notion; a fancy.
 6. Music A theme or motif.
 7. Philosophy
  a. In the philosophy of Plato, an archetype of which a corresponding being in phenomenal reality is an imperfect replica.
  b. In the philosophy of Kant, a concept of reason that is transcendent but nonempirical.
  c. In the philosophy of Hegel, absolute truth; the complete and ultimate product of reason.
8. Obsolete A mental image of something remembered.

Synonyms: idea, thought, notion, concept, conception

 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) Philosophy
  a. a private mental object, regarded as the immediate object of thought or perception
  b. a Platonic Idea or Form
 11. (Music / Classical Music) Music a thematic phrase or figure; motif
 12. Obsolete a mental image
 get ideas to become ambitious, restless, etc
 not one's idea of not what one regards as (hard work, a holiday, etc.)
 that's an idea that is worth considering
 the very idea! that is preposterous, unreasonable, etc.
 [via Late Latin from Greek: model, pattern, notion, from idein to see]

Source

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