Each part of the standard can be purchased separately from ISO or from any of its national member bodies (such as ANSI, BSI, AFNOR, DIN, etc.).

ISO 25964 is for thesauri intended to support information retrieval, and specifically to guide the choice of terms used in indexing, tagging and search queries.

The primary objective is thus summarised in the introduction to the standard as: "If both the indexer and the searcher are guided to choose the same term for the same concept, then relevant documents will be retrieved."

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.

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 of the other KOSs.

Interoperability between the different networks, platforms, software applications, and languages (both natural and artificial) is reliant on the adoption of numerous protocols and standards.

It deals with monolingual lists, synonym rings and taxonomies as well as thesauri, but does not provide a data model, nor address multilingual vocabularies or other aspects of interoperability, such as mapping between KOSs.