Timaeus the Sophist was a Greek philosopher

Greek philosophy

Ancient Greek philosophy arose in the 6th century BCE and continued through the Hellenistic period, at which point Ancient Greece was incorporated in the Roman Empire...

 who lived sometime between the 1st and 4th centuries. Nothing is known about his life. He is the supposed author of a Lexicon of Platonic

Platonism

Platonism is the philosophy of Plato or the name of other philosophical systems considered closely derived from it. In a narrower sense the term might indicate the doctrine of Platonic realism...

 words which is still extant. The Lexicon made use of earlier commentaries on Plato

Commentaries on Plato

Commentaries on Plato refers to the great mass of literature produced, especially in the ancient and medieval world, to explain and clarify the works of Plato...

 which are now lost. It underwent significant additions and subtractions of text during later periods leading to the inclusion of many words which have nothing to do with Plato

Plato

Plato , was a Classical Greek philosopher, mathematician, student of Socrates, writer of philosophical dialogues, and founder of the Academy in Athens, the first institution of higher learning in the Western world. Along with his mentor, Socrates, and his student, Aristotle, Plato helped to lay the...

 or his philosophy. The purpose of the Lexicon was to explain the usage of words and phrases which occur in Plato's works. The first detailed study of the manuscript and edition of the Lexicon was produced in the late 18th century by David Ruhnken

David Ruhnken

David Ruhnken was a Dutch classical scholar of German origin.-Origins:Ruhnken was born in Bedlin near Stolp, Pomerania Province,...

(1754; 2nd ed. 1789) who also provided a detailed commentary. There was a revised version of Ruhnken's second edition by Georg Aenotheus Koch in 1828.