Plato ruined the word ideal for ordinary use — and made it immortal. Greek ἰδέα (idéa) meant 'form' or 'pattern', from ἰδεῖν ('to see'). In everyday Greek, an idea was simply the look or appearance of something. Plato transformed it into the cornerstone of Western philosophy.
In Plato's theory of Forms, the ideal was the perfect, immaterial archetype that exists beyond the physical world. A circle drawn on paper is imperfect — it has bumps, thickness, variation. But the ideal circle exists perfectly in the mind. Every physical object is a flawed copy of its ideal Form.
Late Latin ideālis ('existing as an idea') carried this philosophical freight into English in the 15th century. The word arrived already loaded with Platonic meaning: the ideal was not merely 'good' but 'perfect in conception, imperfect in reality'.
The deeper etymology reveals a striking pattern. The PIE root *weyd- meant 'to see' or 'to know'. From it descended Greek idéa ('what is seen mentally'), Latin vidēre ('to see', giving video, vision, evident), English wit ('knowledge'), wise ('having seen much'), and even history (Greek historía, 'inquiry' — learning by looking). Across every branch, the metaphor is identical: to know something is to have seen it. An ideal is the clearest thing the mind