The headword occurs (genitive case) in Aristophanes, Clouds 166 (web address 1); Aristophanes has coined it for use in Strepsiades' ironic tribute to the sharpsightedness of Chairephon (chi 158, chi 159, chi 160) in discerning an acoustic function in a gnat's anus. Henderson translates it as "enterology" (web address 1 but see English translation), and note Dover ad loc: "Archippos 25.3 uses e)ntereu/ein of a fishmonger gutting fish. It is possible that by di- Ar. means to suggest the many words which imply perspicacity or thoroughness, e.g. dieide/nai, dianoei=sqai, diasko/pein, diereuna=n, etc.".
The Suda's gloss to\ e)rw/thma, also in ps.-Zonaras, follows the scholia vetera, but the noun transmitted is held to be corrupt; it ought to be to\ e)pino/hma or the like.