Plato was an ancient Greek philosopher. He was a student of Socrates, but since no writings by Socrates survive, Plato's writings are the earliest of that line of philosophy which was continued through Aristotle and became the foundation of western thought up to the present day.
Although Aristotle learnt from Plato and Plato's writings underpin his in some respects, their relationship is not as simple as one being a development of the other. Most of the ideas that are considered uniquely Platonic are not present in Aristotle; the best known of these is probably the concept of 'forms'. Plato argued that the purest manifestation of any object was the idea of that object, and any created form of it was necessarily an imperfect copy of the perfect ideal. This central idea lies at the heart of many strands of thinking about language, theology and perception.
Most of Plato's writings are in the form of dialogues, often between Socrates and another interlocutor. In Plato's time, there was no precedent for written works of philosophy, so he adapted the conventions of drama in order to present his ideas.
Plato embodied Greek ideas about a healthy mind and body complementing each other. He was a keen wrestler, and the name Plato is a nickname meaning 'broad' or 'powerfully built'.