Erotianus, (gr. Erotianos), or, as he is sometimes called, Herodianus (Erodianos), the author of a Greek work still extant, entitled Ton par Hippokratei Lexeon Sunagoge Vocums, quae apud Hippocratem sunt, Collectio. It is uncertain whether he was himself a physician, or merely a grammarian, but he appears to have written (or at least to have intended to write) some other works on Hippocrates besides that which we now possess (pp. 23, 208, ed. Franz).

He must have lived (and probably at Rome) in the reign of the emperor Nero, 54-68 AD, as his work is dedicated to his archiater, Andromachus. It is curious as containing the earliest list of the writings of Hippocrates that exists, in which we find the titles of several treatises now lost, and also miss several that now form part of the Hippocratic collection. The rest of the work consists of a glossary, in which the words are at present arranged in a partially alphabetical manner, though it appears that this mode of arrangement is not that which was adopted by the author himself. It was first published in Greek, 8vo., 1564, Paris. in H. Stephani Dictionarium Medicum ; a Latin translation by Barth. Eustachiiis appeared in 1566, 4to., Venet.; the last and best edition is that by Franz, Lips. 1780, 8vo., Greek and Latin, containing also the glossaries of (Galen and Herodotus, a learned and copious commentary, and good indices. It has also been published with some editions of the works of Hippocrates.