the standard as: Whereas most of the applications envisaged for ISO 2788 and ISO 5964 were databases in a single domain, often in-house or for paper-based systems, ISO 25964 provides additional guidance for the new context of networked applications, including the Semantic Web. A thesaurus is one among several types of controlled vocabulary used in this context. ISO 25964 Part 1 A thesaurus compliant with ISO 25964-1 (as Part 1 is known) lists all the concepts available for indexing in a given context, and labels each of them with a preferred term, as well as any synonyms that apply. Relationships between the concepts and between the terms are shown, making it easy to navigate around the field while building up a search query. The main types of relationship include: equivalence (between synonyms and near-synonyms e.g. motor-bikes, motor-cycles and motorcycles) hierarchical (between broader and narrower concepts e.g. flowers and roses) associative (between concepts that are closely related in some non-hierarchical way, e.g. between a disease and the virus that causes that disease) In multilingual thesauri equivalence also applies between corresponding terms in different natural languages. Establishing correspondence is not always easy, and the standard provides recommendations for handling the difficulties that commonly arise. ISO 25964-1 explains how to build a monolingual or a multilingual thesaurus, how to display it, and how to manage its development. There is a data model to use for handling thesaurus data (especially when exchanging data between systems) and an XML schema for encoding the data. Both the model and the schema can be accessed 24/7, free of charge, on the official website hosted by NISO. The standard also sets out the features you should look for when choosing software to manage the thesaurus. ISO 25964 Part 2 ISO 25964-2 deals with the challenges of using one thesaurus in combination with another, and/or with some other type of controlled vocabulary or knowledge organization system (KOS). The types covered include classification schemes, taxonomies, subject heading schemes, ontologies, name authority lists, terminologies and synonym rings. Within a single organization it is common to find several different such KOSs used in contexts such as the records management system, the library catalogue, the corporate intranet, the research lab, etc. To help users with the challenge of running a single search across all the available collections, ISO 25964-2 provides guidance on mapping between the terms and concepts of one thesaurus and those