idea

The word 'idea' entered English in the late 14th century from Latin 'idea', which itself was borrowed from the Ancient Greek 'ἰδέα' (idéa), meaning "form, pattern, concept, notion." The Greek term derives from the verb 'εἴδω' (eídō), meaning "to see." This etymological journey reveals a fascinating conceptual shift from the physical to the mental: the original sense was tied to the visual—the "look" or "form" of something. Through Platonic philosophy, 'idea' was elevated to signify an archetypal, perfect form existing in the realm of thought. This philosophical abstraction was then generalized in Latin and later in English to denote any mental conception, plan, or belief, completing its evolution from a concrete act of seeing to an abstract act of thinking.

The word 'idea' is a simplex loanword from Greek, borrowed into English via Latin and French. It does not contain separable morphemes in its modern English spelling.