Idea is in Greek a form or an image. The word signified in early philosophical use the archetype or primal image which the Platonic philosophy suppose more..Idea is in Greek a form or an image. The word signified in early philosophical use the archetype or primal image which the Platonic philosophy supposed to be the model or pattern that existing objects imperfectly embody. This high sense has nearly disappeared from the word idea, and has been largely appropriated by ideal, tho something of the original meaning still appears when in theological or philosophical language we speak of the ideas of God. The present popular use of idea makes it to signify any product of mental apprehension or activity, considered as an object of knowledge or thought; this coincides with the primitive sense at but a single point--that an idea is mental as opposed to anything substantial or physical; thus, almost any mental product, as a belief, conception, design, opinion, etc., may now be called an idea. Compare FANCY; IDEAL.(noun)