[ ahy-dee-uh, ahy-deeuh ]
See synonyms for: ideaideas on

  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.

  1. an impression: He gave me a general idea of how he plans to run the department.

  2. an opinion, view, or belief: His ideas on raising children are certainly strange.

  3. a plan of action; an intention: the idea of becoming an engineer.

  4. a groundless supposition; fantasy.

  5. Philosophy.

    • a concept developed by the mind.

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

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

    • Kantianism. idea of pure reason.

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

  7. Obsolete.

    • a likeness.

    • a mental image.

Origin of idea

First recorded in 1400–50; from Late Latin from Greek idéā “form, pattern,” equivalent to ide- (stem of ideîn “to see”) + feminine noun ending; replacing late Middle English idee from Middle French from Late Latin, as above; akin to wit1

word story For idea

English idea comes from one of Seneca’s Epistles (58), written about a.d. 64 during his retirement from Emperor Nero’s court, in which the Roman philosopher uses idea in the sense of “Platonic idea, eternal archetype.” Seneca wrote idea in Latin letters; the Roman orator Cicero, about a hundred years earlier, wrote the same word, with the same meaning, but in Greek letters. Plato used the perfectly ordinary Greek noun idéa “form, shape” as a term in logic meaning “classification, principle of classification,” and in his own metaphysics to mean “ideal form, prototype.” In fact, the earliest uses of idea in English show semantic overlap with ideal. The familiar and current meanings having to do with a mental conception, notion, or image first appeared in the late 16th century.
The Greek noun idéa comes from the very common, very complicated Proto-Indo-European root weid-, woid-, wid- “to see.” In Greek the variant woid- forms the verb oîda ( woîda in some dialects), meaning “I know.” (In form, oîda is a perfect tense used to show a present state: “I have seen, I know.”)
Woidos, a noun derived from woid-, becomes veda- “knowledge” in Sanskrit ( Rig-Veda means “knowledge of the hymns, sacred stanzas”). The variant wid- forms the Greek noun idéa, and the infinitive ideîn (also wideîn ), the Latin infinitive vidēre, and the Slavic (Czech) vidět, all meaning “to see.”
Weid-, woid-, wid- become wīt-, wait-, wit- in Germanic. The suffixed form wīt-to- forms the adjective wīsaz, Old English wīs (English wise ), and Old English wīsdōm “learning” (English wisdom ).

Other words for idea

Other words from idea

  • i·de·a·less, adjective
  • pre·i·de·a, noun
  • sub·i·de·a, noun

Words Nearby idea Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use idea in a sentence

British Dictionary definitions for idea (1 of 2)


/ (aɪˈdɪə) /

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

  2. the thought of something: the very idea appals me

  1. a mental representation of something: she's got a good idea of the layout of the factory

  2. the characterization of something in general terms; concept: the idea of a square circle is self-contradictory

  3. an individual's conception of something: his idea of honesty is not the same as yours and mine

  4. the belief that something is the case: he has the idea that what he's doing is right

  5. a scheme, intention, plan, etc: here's my idea for the sales campaign

  6. a vague notion or indication; inkling: he had no idea of what life would be like in Africa

  7. significance or purpose: the idea of the game is to discover the murderer

  8. philosophy

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

    • a Platonic Idea or Form

  9. music a thematic phrase or figure; motif

  10. obsolete a mental image

  11. get ideas to become ambitious, restless, etc

  12. not one's idea of not what one regards as (hard work, a holiday, etc)

  13. that's an idea that is worth considering

  14. the very idea! that is preposterous, unreasonable, etc

Origin of idea

C16: via Late Latin from Greek: model, pattern, notion, from idein to see

usage For idea

It is usually considered correct to say that someone has the idea of doing something, rather than the idea to do it: he had the idea of taking (not the idea to take) a short holiday

Derived forms of idea

  • idealess, adjective

British Dictionary definitions for Idea (2 of 2)


/ (aɪˈdɪə) /

  1. another name for Form

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Idioms and Phrases with idea


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

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.