The _bilingual_ (Gr.-Lat., Lat.-Gr.) glossaries also point to an early period, and were used by the grammarians (1) to explain the peculiarities (_idiomata_) of the Latin language by comparison with the Greek, and (2) for instruction in the two languages (Charis. 254. 9, 291. 7, 292. 16 sqq.; Marschall, _De Q. Remmii P. libris gramm. 22_; Goetz, _Corp. gloss. lat._ ii. 6).
For the purposes of grammatical instruction (Greek for the Romans, Latin for the Hellenistic world), we have systematic works, a translation of Dositheus and the so-called _Hermeneutica_, parts of which may be dated as early as the 3rd century A.D., and lexica (cf. Schoenemann, _De lexicis ant._ 122; Knaack, in _Phil. Rundsch._, 1884, 372; Traube, in _Byzant. Ztschr._ iii. 605; David, _Comment. Ien._ v. 197 sqq.).
The most important remains of bilingual glossaries are two well-known lexica; one (Latin-Greek), formerly attributed (but wrongly, see Rudorff, in _Abh.. Akad. Berl._, 1865, 220 sq.; Loewe, _Prodr._ 183, 190; Mommsen, _C.I.L._ v. 8120; A. Dammann, _De Festo Pseudo-philoxeni auctore_, 12 sqq.; Goetz, _Corp._ ii. 1-212) to Philoxenus (consul A.D. 525), clearly consists of two closely allied glossaries (containing glosses to Latin authors, as Horace, Cicero, Juvenal, Virgil, the Jurists, and excerpts from Festus), worked into one by some Greek grammarian, or a person who worked under Greek influence (his alphabet runs A, B, G, D, E, &c.); the other (Greek-Latin) is ascribed to Cyril (Stephanus says it was found at the end of some of his writings), and is considered to be a compilation of not later than the 6th century (Macrobius is used, and the _Cod. Harl._, which is the source of all the other MSS., belongs to the 7th century); cf. Goetz, _Corp._ ii. 215-483, 487-506, praef. _ibid._ p. xx. sqq. Furthermore, the bilingual medico-botanic glossaries had their origin in old lists of plants, as Ps.-Apuleius in the treatise _De herbarum virtutibus_, and Ps.-Dioscorides (cf. M. Wellmann, _Hermes_, xxxiii. 360 sqq., who thinks that the latter work is based on Pamphilus, q.v.; Goetz, _Corp._ iii.); the glossary, entitled _Hermeneuma_, printed from the _Cod. Vatic._ reg. Christ. 1260, contains names of diseases.