Etymology: Middle English, from Latin, from Greek, from idein to see — more at wit
Date: 14th century
a. a transcendent entity that is a real pattern of which existing things are imperfect representations
b. a standard of perfection ; ideal
c. a plan for action ; design
2. archaic a visible representation of a conception ; a replica of a pattern
a. obsolete an image recalled by memory
b. an indefinite or unformed conception
c. an entity (as a thought, concept, sensation, or image) actually or potentially present to consciousness
4. a formulated thought or opinion
5. whatever is known or supposed about something <a child's idea of time> 6. the central meaning or chief end of a particular action or situation 7. Christian Science an image in Mind • idealess adjective Synonyms: idea, concept, conception, thought, notion, impression mean what exists in the mind as a representation (as of something comprehended) or as a formulation (as of a plan). idea may apply to a mental image or formulation of something seen or known or imagined, to a pure abstraction, or to something assumed or vaguely sensed <innovative ideas> <my idea of paradise>. concept may apply to the idea formed by consideration of instances of a species or genus or, more broadly, to any idea of what a thing ought to be <a society with no concept of private property>. conception is often interchangeable with concept; it may stress the process of imagining or formulating rather than the result <our changing conception of what constitutes art>. thought is likely to suggest the result of reflecting, reasoning, or meditating rather than of imagining <commit your thoughts to paper>. notion suggests an idea not much resolved by analysis or reflection and may suggest the capricious or accidental <you have the oddest notions>. impression applies to an idea or notion resulting immediately from some stimulation of the senses <the first impression is of soaring height>.
New Collegiate Dictionary. 2001.