The Forms or Ideas, eidē, are for Plato the true objects of knowledge: perfect, eternal and unchanging, grasped by the intellect, not the senses. Sensible things participate in them imperfectly. The highest is the Form of the Good, which makes the others knowable as the sun makes things visible.
Forms
Plato’s eternal, unchanging realities, such as Beauty and Justice, of which things in the world are images.
Also: Ideas, eidos