- something one thinks, knows, or imagines; a thought; mental conception or image; notion
- an opinion or belief
- a plan; scheme; project; intention; aim
- a hazy perception; vague impression; fanciful notion; inkling
- meaning or significance
- Music a theme or figure
- Philos. according to Plato, any of the unchanging, eternal, intelligible models or archetypes of which all material things are only imperfect imitations and from which their existence derives: in modern philosophy, used variously to mean the immediate object of thought, absolute truth, etc.
Origin of ideaClassical Latin from Gr, form or appearance of a thing as opposed to its reality from Indo-European an unverified form widswo- from base an unverified form weid-, to see, know from source Classical Latin videre, to see, Classical Greek idein, to see, Old English witan, to know