1. Something, such as a thought or conception, that is the product of mental activity.
2. An opinion, conviction, or principle: has some strange political ideas.
3. A plan, purpose, or goal: She started school with the idea of becoming a doctor.
4. The gist or significance: The idea of the article is that investing in green technology can save you money in the long run.
5. A sense that something can happen; a notion or expectation: They have this idea that we can just drop what we're doing and go to the park.
6. Music A theme or motif.
a. In the philosophy of Plato, a non-physical form or archetype to which beings in phenomenal reality correspond only as imperfect replicas.
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.
[Middle English, from Latin, from Greek; see weid- in the Appendix of Indo-European roots.]
Synonyms: idea, thought, notion, concept, conception
These nouns refer to what is formed or represented in the mind as the product of mental activity. Idea has the widest range: “Human history is in essence a history of ideas” (H.G. Wells).
Thought is distinctively intellectual and stresses contemplation and reasoning: She gathered her thoughts before she spoke. Notion suggests an often intuitive idea or image conceived by the mind: “All that came to mind was a notion of galactic space, of spirals, the Horse Nebula, all of which were distant and mysterious and cold” (Craig Nova).
Concept and conception are applied to mental formulations on a broad scale: You seem to have absolutely no concept of time. “Every succeeding scientific discovery makes greater nonsense of old-time conceptions of sovereignty” (Anthony Eden).
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
The American Heritage Dictionary Blog
Check out our blog, updated regularly, for new words and revised definitions, interesting images from the 5th edition, discussions of usage, and more.