Hierarchy. A partial ordering of entities according to some relation. A type hierarchy is a partial ordering of concept types by the type-subtype relation. In lexicography, the type-subtype relation is sometimes called the hypernym-hyponym relation. A meronomy is a partial ordering of concept types by the part-whole relation. Classification systems sometimes use a broader-narrower hierarchy, which mixes the type and part hierarchies: a type A is considered narrower than B if A is subtype of B or any instance of A is a part of some instance of B. For example, Cat and Tail are both narrower than Animal, since Cat is a subtype of Animal and a tail is a part of an animal. A broader-narrower hierarchy may be useful for information retrieval, but the two kinds of relations should be distinguished in a knowledge base because they have different implications. “ (Sowa, 2004).


“A hierarchy is a type of order based on relations of priority (anterioty) and posterity. A clarification of this definition requires a specification of the principle that constitutes order as such . . .. “ de Muralt (1991, p. 352).


In thesauri are the specifications of hierarchical relations between terms such as broader terms (BT) and narrower terms (NT) normally central features. Sometimes the kind of hierarchical relation is also specified, e.g. BTG for generic broader terms, BTP for partitive broader terms or BTI for broader term for an individuel instance (cf., National Information Standards Organization (NISO), 1998).


Hodge (2000, chapter 1) find that Classification Schemes, Taxonomies, and Categorization Schemes may not follow the rules for hierarchy required in the ANSI NISO Thesaurus Standard (Z39.19) (NISO 1998), and they lack the explicit relationships presented in a thesaurus “ In an email to the author (8 jan 2004) Hodge wrote: “ What I meant was that often classification schemes, categorization schemes and taxonomies do not follow the rules for determining BTs, NTs verus RTs. It isn't that they don't identify types of BT or NT relationships, but that the general rules for whole/part, etc. may often be broken. For example, a term may be made subordinate to another term simply because it makes sense to the user or in the case of taxonomies because the developer wants to limit the depth of the scheme, not because it is really generic or whole/part.
I'm not saying that all thesauri follow the NISO standard to the letter either. Many do not. However, I've found that many who develop classification schemes or subject categories do not even know that the NISO standard exists. In the case of thesaurus developers, most know that it exists, but they may choose to ignore certain aspects of it because it makes more sense in their environment.”

"Compared to traditional classification schemes this is [topic maps] very different. First of all, we no longer have a hierarchy but a network of subjects. Secondly, the relationships between the subjects are clearly defined instead of being generic. From the point of view of searching, this is very powerful, since it allows us to do queries like "show me all technologies used with topic maps", or "show me every interchange format based on SGML", and so on." (Garshol, 2004).



parent/child relationship




(from Michel, 1997)

Class/instance pairs
Genus/species pairs
Non-inclusion hierarchical relationships
Genealogical relationships
Generic predecessor relationships*
Organizational reporting
Partitive relationships*
Composition partitive relationships*
Comprehensive partitive relationships*
Intrinsic partitive relationships*
Whole/part pairs*
Non-physical whole/part pairs*
Physical whole/part pairs*

Anatomical whole/part pairs*
Anatomical organ whole/part pairs*
Anatomical system whole/part pairs*
Artifact whole/part pairs*
Geographic whole/part pairs*
Topic inclusion*
Discipline/subdiscipline pairs*
Whole/attachment pairs*
Whole/integral part pairs*
Whole/piece pairs*
Whole/segmental part pairs*
Whole/systemic part pairs*
Anatomical system whole/part pairs*










Aberra, D. A. (2006). The hierarchical relationship of words: Superordinate, hyponym and subordinate. UAWPL [University of Alberta Working Papers in Linguistics], vol. 1. Available at:  http://www.uofaweb.ualberta.ca/linguistics/pdf/UAWPvol1DA.pdf


Ahl, V. & Allen, T. (1996). Hierarchy theory: a vision, vocabulary and epistemology, New York: Columbia University Press.


Allen, T. F. H. & Starr, T. B. (1982). Hierarchy: perspectives for ecological complexity. Chicago: University of Chicago Press.


Cole, S. (1983), "The hierarchy of the sciences?", American Journal of Sociology, 89(1), 111-139.


Garshol, L. M. (2004) Metadata? Thesauri? Taxonomies? Topic maps! Making sense of it all. Journal of Information Science, 30 (4). 378-391. Available online at: http://www.ontopia.net/topicmaps/materials/tm-vs-thesauri.html


Hodge, G. (2000). Systems of Knowledge Organization for Digital libraries. Beyond traditional authority files. Washington, DC : the Council on Library and Information Resources. http://www.clir.org/pubs/reports/pub91/contents.html


Laudan, L. (1984). Science and values. The aims of science and their role in scientific debate. Berkeley: University of California Press. (Chapter two: The hierarchical structure of scientific debates, pp. 23-41).


Lee, H. L. & Olson, H. A. (2005). Hierarchical navigation: An exploration of Yahoo! directories. Knowledge Organization, 32(1), 10-24.


Michel, D. (1997). Appendix B: Taxonomy of Subject Relationships. IN: ALA. American Library Association. ALCTS. Association for Library Collections & Technical Services. Final Report to the ALCTS/CCS Subject Analysis Committee. Subcommittee on Subject Relationships/Reference Structures. http://www.ala.org/ala/alctscontent/catalogingsection/catcommittees/subjectanalysis/subjectrelations/finalreport.htm


Michel, D. (1999). Appendix B: Taxonomy of Subject Relationships. Part  1 (Direct link):



Part 2: http://www.ala.org/ala/alctscontent/catalogingsection/catcommittees/subjectanalysis/subjectrelations/appendixbpartii.htm




De Muralt, A. (1991). Hierarchy. IN: Burkhardt, H. & Smith, B. (eds.): Handbook of Metaphysics and Ontology. Vol. 1-2 (vol. 1, pp. 352-354). Munich: Philosophia,

National Information Standards Organization (NISO). 1998. ANSI/NISO Z39.19. Guidelines for the Construction, Format and Management of Monolingual Thesauri.



O'Neill, R. V., DeAngelis, D. L., Waide, J. B., & Allen, T. F. H. (1986). A hierarchical concept of ecosystems. Princeton: Princeton University.


Olson, Hope A. (1999). Exclusivity, teleology and hierarchy: Our Aristotelian legacy. Knowledge Organization 26(2): 65-73.


Patrides, C. A. (1973-74). Hierarchy and order. IN: Wiener, P. P. : The Dictionary of the History of Ideas: Studies of Selected Pivotal Ideas. New York: Charles Scribner's Sons. (Vol. 2, pp. 435-449). Available (without illustrations): http://etext.lib.virginia.edu/cgi-local/DHI/dhi.cgi?id=dv2-50


Salthe, S. N. (2001). Summary of the Principles of Hierarchy Theory. http://www.nbi.dk/~natphil/salthe/hierarchy_th.html  (Visited January 1, 2004).


Sowa, (2004). Glossary. [Ontology]. http://www.jfsowa.com/ontology/gloss.htm . Last Modified01/01/2004 18:07:16


Wikipedia, the free encyclopedia.(2005). Hierarchy. http://en.wikipedia.org/wiki/Hierarchy


Willett, P. (1988). Trends in Hierarchic Document Clustering: A Critical Review. Information Processing and Management, 24(5), 577-597.




See also: Generic relation


Birger Hjørland

Last edited: 04-05-2007