_Dictionarium_ is a word of low or modern Latinity;[1] _dictio_, from which it was formed, was used in medieval Latin to mean a word. _Lexicon_ is a corresponding word of Greek origin, meaning a book of or for words--a dictionary. A _glossary_ is properly a collection of unusual or foreign words requiring explanation. It is the name frequently given to English dictionaries of dialects, which the Germans usually call _idioticon_, and the Italians _vocabolario_. _Wörterbuch_, a book of words, was first used among the Germans, according to Grimm, by Kramer (1719), imitated from the Dutch _woordenboek_. From the Germans the Swedes and Danes adopted _ordbok_, _ordbog_. The Icelandic _ordabôk_, like the German, contains the genitive plural. The Slavonic nations use _slovar_, _slovnik_, and the southern Slavs _ryetshnik_, from _slovo_, _ryetsh_, a word, formed, like dictionary and lexicon, without composition. Many other names have been given to dictionaries, as _thesaurus_, _Sprachschatz_, _cornucopia_, _gazophylacium_, _comprehensorium_, _catholicon_, to indicate their completeness; _manipulus predicantium_, _promptorium puerorum_, _liber memorialis_, _hortus vocabulorum_, _ionia_ (a violet bed), _alveary_ (a beehive), _kamoos_ (the sea), _haft kulzum_ (the seven seas), _tsze tien_ (a standard of character), _onomasticon_, _nomenclator_, _bibliotheca_, _elucidario_, _Mundart-sammlung_, _clavis_, _scala_, _pharetra_,[2] _La Crusca_ from the great Italian dictionary, and _Calepino_ (in Spanish and Italian) from the Latin dictionary of Calepinus.
The tendency of great dictionaries is to unite in themselves all the peculiar features of special dictionaries. A large dictionary is most useful when a word is to be thoroughly studied, or when there is difficulty in making out the meaning of a word or phrase. Special dictionaries are more useful for special purposes; for instance, synonyms are best studied in a dictionary of synonyms. And small dictionaries are more convenient for frequent use, as in translating from an unfamiliar language, for words may be found more quickly, and they present the words and their meanings in a concentrated and compact form, instead of being scattered over a large space, and separated by other matter. Dictionaries of several languages, called _polyglots_, are of different kinds. Some are polyglot in the vocabulary, but not in the explanation, like Johnson's dictionary of Persian and Arabic explained in English; some in the interpretation, but not in the vocabulary or explanation, like _Calepini octoglotton_, a Latin dictionary of Latin, with the meanings in seven languages. Many great dictionaries are now polyglot in this sense. Some are polyglot in the vocabulary and interpretation, but are explained in one language, like Jal's _Glossaire nautique_, a glossary of sea terms in many languages, giving the equivalents of each word in the other languages, but the explanation in French. Pauthier's _Annamese Dictionary_ is polyglot in a peculiar way. It gives the Chinese characters with their pronunciation in Chinese and Annamese. Special dictionaries are of many kinds. There are technical dictionaries of etymology, foreign words, dialects, secret languages, slang, neology, barbarous words, faults of expression, choice words, prosody, pronunciation, spelling, orators, poets, law, music, proper names, particular authors, nouns, verbs, participles, particles, double forms, difficulties and many others. Fick's dictionary (Göttingen, 1868, 8vo; 1874-1876, 8vo, 4 vols.) is a remarkable attempt to ascertain the common language of the Indo-European nations before each of their great separations. In the second edition of his _Etymologische Forschungen_ (Lemgo and Detmoldt, 1859-1873, 8vo, 7217 pages) Pott gives a comparative lexicon of Indo-European roots, 2226 in number, occupying 5140 pages.