T HE making of dictionaries is a very ancient art. Arabic, Latin, and Greek scholars compiled lists of words, treating their analogies, origins and differences. In the early stages works of this nature assumed diverse titles such as vocabulary, applied to a word-list with concise definitions; glossary, a collection of archaic, rare, dialectical, or antiquated words with no attempt at completeness; lexicon, a Greek word which in the Middle Ages referred to rare and difficult terms, although at present it is generally restricted to the vocabulary of a given author or his works: it is also applied to dictionaries of Greek, Latin, and Hebrew; and thesaurus, a collection of the words of a language. The as known today is of modern origin. It is the outgrowth of works of criticism on Greek and Latin literatures by scholars of the Middle Ages; it is perhaps the development of the medieval custom of writing marginal glosses or explanatory notes in texts of classical authors. Up to the fifteenth century lexicography was a series of incomplete essays, but with the discovery of printing there developed an increasing fondness for the study of the classics and with it the necessity to overcome the difficulties in the art of languages. The monks of Port Royal in the fifteenth century were the first to undertake a scientific approach to grammar and lexicography. The word dictionarius is supposed to have been first used by the English Johannes de Garlandia of the fourteenth century (1275?-1350), in a collection of Latin words, Multorum vocabulorum aequivocorum, arranged according to subjects, in sentences, and entirely in Latin. It appeared in print in Deventer in 1490. The author defines the term dictionary as Dictionarius dicitur libellus iste a dictionibus magis necessariis, quas tenetur quilibet scolaris, non tantum in scrinio de lignis facto sed in cordis armariolo firmiter retinere.