What is "euphraeus"

Euphraeus (; fl. c. 4th century BCE; d. ca. 342 BCE/341 BCE) was a philosopher and student of Plato from the town of Oreus in northern Euboea. He appears to have been active in politics in addition to his speculative studies, being first an adviser to Perdiccas III of Macedon and then an opponent of Philip II and his supporters in Oreus. Information regarding his life is scant, however, and few facts about it are mentioned in more than one source. He appears in the Fifth Letter of Plato, Demosthenes' Third Philippic, and Athenaeus' Deipnosophistae (which repeats the information about him contained in the now-lost Historical Notes by Carystius of Pergamum).