(Δίδυμος), a Greek medical writer who lived perhaps in the third century after Christ, as he is quoted by Aetius (tetrab. ii. serm. 2.100.15, p. 256) and Alexander Trallianus (De Med. 7.13, p. 235), by whom he is called σοφώτατος. He may perhaps be the native of Alexandria who is mentioned by Suidas as having written fifteen books on Agriculture, and who is frequently quoted in the collection of writers called Geoponici (lib. i. 100.5, 2.3, 14, 17, 26, &c., ed. Niclas.). His writings would seem to have been extant in the seventeenth century, or at least they were supposed to be so, as Salmasius expected to receive a MS. of his work de Plantis from Italy. (Life prefi ed to his Letters, p. 39.)