The concept of the onomasiological dictionary presupposes the converse relation between onomasiology and semasiology, for which see the corresponding section. Although that volume of a bilingual dictionary which leads from the user language to the foreign language is essentially an onomasiological dictionary, as explained elsewhere, the term ‘onomasiological dictionary’ commonly designates a monolingual dictionary. Under that proviso, an onomasiological dictionary is a dictionary which is organized by semantic criteria and thus leads the user from concepts to expressions.

There are two kinds of onomasiological dictionaries as distinguished by their macrostructure:

• thesaurus (German Wörterbuch nach Sachgruppen ‘dictionary of subject matter’)
• synonym dictionary (German Synonymenwörterbuch)

Thesaurus

The macrostructure of a thesaurus is based on an ontology (a theory of the world). The most influential dictionary of this kind is Roget 1852 (“Roget's Thesaurus”). A well-known German onomasiological dictionary is Dornseiff 1959. A proposal of such an ontology for the lexicographer is Hallig & Wartburg 1963.

For several reasons, the classification (see the treatment of Klassifikation) of concepts in a thesaurus has mostly been attempted in the form of a hierarchical classification. The world of concepts is divided into a limited number of conceptual fields, each of which is again articulated in a number of subfields, arriving thus at lexical fields (in the sense of early 20th cent. semantics). At the lowest level, concepts are individuated and then paired with expressions, some of which may be synonymous.

The upper levels of Roget's hierarchy are as follows:

Roget, Peter M. 1852, Thesaurus of English words and phrases, classified and arranged so as to facilitate the expression of ideas and assist in literary composition. London etc.: Longmans, Green & Co.

Roget's complete classification in Wikipedia

Dornseiff has hundreds of classes at the second level; the following are his main divisions:

Dornseiff, Franz 1959, Der deutsche Wortschatz nach Sachgruppen, mit alphabetischem Generalregister. Berlin: W. de Gruyter (5. Auflage).

Hallig & Wartburg's classification was meant to serve as a basis for the production of dialect dictionaries:

A classification of concepts is independent of structural features of the signs expressing them. Therefore all of Roget's and Dornseiff's principal classes contain members of all word classes. At the lower levels of the hierarchy, however, grammatical categories start playing a role. In Dornseiff, they are a principle of classification at the third level.

The structure of a print thesaurus essentially reduces to its multi-level macrostructure. Although there may, at the head of a section, be cross-references to other sections, the lexical items themselves are listed without any microstructure. Apart from its onomasiological macrostructure, a thesaurus may contain an alphabetic index.

While the form of traditional thesauri is, to a certain extent, influenced by the print medium, modern electronic implementations tend to take the form of a conceptual network. An important example is Wordnet, which was initially formulated in English, but as it was meant as a system of concepts rather than words, has meanwhile been translated into other European languages.

Dictionary of synonyms

A dictionary of synonyms is a dictionary that enumerates, in the microstructure of each entry, total and partial synonyms of the lemma. It may also list other co-hyponyms of the lemma. While a thesaurus may be more of theoretical interest than of practical use, a dictionary of synonyms is decidedly destined for the writer who wants to find the appropriate expression (German treffender Ausdruck).¹

The macrostructure of a dictionary of synonyms is an alphabetical entry list. From among the total vocabulary of a language, those words are selected as lemmas that typically enter into relations of (partial) synonymy. That is, grammatical formatives, proper names and technical terms are generally excluded from dictionaries of synonyms, while the basic vocabulary figures prominently.

The microstructure of an entry may comprise the following elements:

1. word class
2. subdivision by different senses
3. meaning definition
4. example
5. list of (partial) synonyms, including phrases and idioms
6. list of other kinds of co-hyponyms

Since the lemmas are words of a language rather than concepts, the first thing to take care of in the microstructure is polysemy. This essentially creates subentries, which are sometimes numbered, sometimes only set off by punctuation (e.g. ‘||’). Elements #3 – 6 are then local to each sense.

Since it is the purpose of a dictionary of synonyms to help the user express himself adequately, each of the synonyms listed is optionally accompanied by a marking of the language variety such as ‘regional’, ‘informal’, ‘slang’.

Often, there is a distinction between major and minor entries, in the following sense:

• a major entry comprises a meaning definition and the full set of synonyms,
• a minor entry reduces to the lemma, followed by a reference to one or more major entries.

Thus, Roget's II has the following minor and major entry:

sob verb cry

cry verb
1. To make inarticulate sounds of grief or pain, usu. accompanied by tears: The child cried after falling down
Syns: bawl, blub, blubber, boohoo, howl, keen², sob, wail, weep, yowl.
2. advertise.
3. exclaim.
4. roar.
5. shout.

Similarly, Knaurs dictionary has the following two entries:

schluchzen → weinen

weinen: Tränen vergießen, s. in Tränen auflösen, in Tränen zerfließen/schwimmen, s. der Tränen nicht erwehren können, feuchte Augen bekommen, schluchzen, wimmern; ugs.: heulen, flennen, greinen, plärren, Konzert machen, quarren, quäken, jaulen; reg.: plinsen, piensen

As is clear from the examples, the words assembled in an entry are far from strictly synonymous. Therefore, if the dictionary does not provide meaning definitions (as the Knaurs dictionary does not), it serves the user in reminding him of expressions that he does know rather than in widening his semantic horizon.

The approach of a dictionary of synonyms

While a thesaurus may – and should – take a purely onomasiological approach, dictionaries of synonyms are mostly like the two introduced above in taking a mixed approach:

• Taking an expression of a language – instead of a concept – as the initial point of departure is a semasiological approach. Likewise, the alphabetical order of the keywords is a semasiologically oriented macrostructure.
• In a second step, homonymous and polysemous keywords are monosemized (delimited as an unambiguous meaning). Thus, concepts are identified. Taking these as a second level point of departure for the next step is an onomasiological procedure.
• Then synonyms and other paradigmatically related meanings are associated. This is an onomasiological procedure.

Such a mixed approach is taken for practical reasons. To that extent, however, a dictionary of synonyms is not simply a clear example of an onomasiological dictionary.

¹ In this connection, it is interesting to note that the 20th cent. editors of Roget's thesaurus produced a Roget's II: the new thesaurus, which is a dictionary of synonyms (i.e. it has an alphabetical entry list instead of Roget's ontology), objecting to Roget that he “groups words by association rather than by meaning.”

References

Dornseiff, Franz 2003, Der deutsche Wortschatz nach Sachgruppen. Berlin & New York: W. de Gruyter (8., völlig neu bearb. ... Aufl.).

Hallig, Rudolf & Wartburg, Walther von 1963, Begriffssystem als Grundlage fur die Lexikographie. Versuch eines Ordnungsschemas. Berlin: Akademie-Verlag (2nd ed.).

Radszuweit, Siegrid & Spalier, Martha 1982, Knaurs Lexikon der sinnverwandten Worter. 20 000 Stichworter mit ihren Synonymen. Munchen & Zurich: Droemer Knaur.

Roget, Peter M. 1852, Thesaurus of English words and phrases. classified and arranged so as to facilitate the expression of ideas and assist in literary composition. London etc.: Longmans, Green & Co.

s.ed. 1984, Roget's II. The new thesaurus. New York: Berkley (Condensed version of the homonymous publication by Houghton Mifflin, 1980).