The term ‘form’ is often used to translate the Greek term ‘eidos’ in Plato’s philosophy; a better translation would be the word ‘idea’ both because ‘form’ strongly connotes shape in English, and Plato’s “forms” (or ideas) have no spacial properties, and the English word ‘idea’ is directly derived from the Greek ‘eidos’.

It is important to note, however, that for Plato an eidos is not a cognitive state as the English word might connote, nor is it a thought in the mind of a conscious being at all. For Plato an eidos is a real thing that exists independently of the material world (see Metaphysical Realism). The more standard term used in contemporary Metaphysics is ‘universal’.