Plato

Plato (c.429–c.347 bc), Greek philosopher. A disciple of Socrates and the teacher of Aristotle, he founded the Academy in Athens. An integral part of his thought is the theory of ‘ideas’ or ‘forms’, in which abstract entities or universals are contrasted with their objects or particulars in the material world. His philosophical writings are presented in the form of dialogues, with Socrates as the principal speaker; they include the Symposium and the Timaeus. Plato's political theories appear in the Republic, in which he explored the nature and structure of a just society.

Platonism is the philosophy of Plato or his followers; any of various revivals of Platonic doctrines or related ideas, especially Neoplatonism and Cambridge Platonism (a 17th–century attempt to reconcile Christianity with humanism and science).
Platonic love love which is intimate and affectionate but not sexual. The term is recorded in English from the mid 17th century; the equivalent Latin term amor platonicus was used synonymously with amor socraticus by Ficinus (the Florentine Marsilio Ficino, 1433–99), president of Cosmo de' Medici's Accademia Platonica, to denote the kind of interest in young men with which Socrates was credited.
Platonic solid one of five regular solids (i.e., having all sides and all angles equal), a tetrahedron, cube, octahedron, dodecahedron, or icosahedron. Formerly also called Platonic body.
Platonic year a cycle, imagined by some ancient astronomers, in which the heavenly bodies were supposed to go through all their possible movements and return to their original relative positions, after which, according to some, all history would repeat itself (sometimes identified with the period of precession of the equinoxes, about 25,800 years). Also called great year.