Semantic Web form for topical systems. On the Semantic Web, the term “topical system” is not as commonplace as the phenomenon itself. To illustrate, the term topical occurs in only four LOV vocabularies — not one of which has a clear focus on capturing topical systems.30 This result begs the question of what terminology is employed on the Semantic Web instead. The answer can be found in one of the meanings of the word thesaurus. As Xxxxxxxx Xxxxxxxx states, one sense of the word is that of a ‘terminological database’ or ‘index’.31 The OED defines this particular sense, first attested in 1957, as follows: “A classified list of terms, esp. key-words, in a particular field, for use in indexing and information retrieval.”32 In essence, this sense of thesaurus coincides with what is known as the topical system in historical language thesauri: concepts or labels that are arranged in a hierarchical manner, typically based on the semantics of these concepts, in order to index 28This chapter was written in December 2017. The LOV repository has grown since and, on 18 April 2022, contains information on 774 vocabularies. 29See Van Assem et al., ‘A Method for Converting Thesauri to RDF/OWL’; and Van Assem et al., ‘A Method to Convert Thesauri to SKOS’. 30LOV, s.v. ‘dbpedia-owl’, ‘gold’, ‘lmm1’, ‘xxxxx’. 31Encyclopedia of Language & Linguistics, s.v. ‘Thesauruses’, by Xxxxxxxx. 32OED, s.v. ‘thesaurus, n.’, sense 2c. – or categorize – information in various forms. I will henceforth use the term indexing thesaurus to denote this specific sense of thesaurus. Before discussing the results of searching LOV for appropriate data vocabularies for indexing thesauri, it should be noted that DWBP already explicitly mentions two data models that are used to capture and exchange such thesauri. These data models, which are considered relatively straightforward 115 3 since “complex formalisms are most often not needed” for indexing thesauri, are the ISO 25964 data model and W3C’s Simple Knowledge Organization System (SKOS) vocabulary.33 The first-mentioned model is part of the ISO 25964 standard by the International Organization for Standardization. This standard contains guidelines on the development of indexing thesauri and proposes a data model to encourage exchange and interoperability. The current body maintaining the ISO 25964 standard, NISO, recognizes similarities between the international standard (which is divided over two parts) and SKOS. ISO 25964-1 essentially advises on the selection and fitting together of ...
