Taxonomy is a practice and science concerned with classification or categorization. Typically, there are two parts to it: the development of an underlying scheme of classes (a taxonomy) and the allocation of things to the classes (classification).
Originally, taxonomy referred only to the classification of organisms on the basis of shared characteristics. Today it also has a more general sense. It may refer to the classification of things or concepts, as well as to the principles underlying such work. Thus a taxonomy can be used to organize species, documents, videos or anything else.
A taxonomy organizes taxonomic units known as "taxa" (singular "taxon"). Many are hierarchies.
One function of a taxonomy is to help users more easily find what they are searching for. This may be effected in ways that include a library classification system and a search engine taxonomy.
Though often used interchangeably, taxonomies are distinct from typologies in that the former are concerned with empirical and objective characteristics, while the latter are concerned with abstract or subjective criteria.
Etymology The word was coined in 1813 by the Swiss botanist A. P. de Candolle and is irregularly compounded from the Greek , taxis 'order' and , nomos 'law', connected by the French form ; the regular form would be , as used in the Greek reborrowing . (partially updated December 2021), s.v.review of Aperçus de Taxinomie Générale in Nature 60:489–490 (1899)
Applications Wikipedia categories form a taxonomy,Zirn, Cäcilia, Vivi Nastase and Michael Strube. 2008. "Distinguishing Between Instances and Classes in the Wikipedia Taxonomy" (video lecture). 5th Annual European Semantic Web Conference (ESWC 2008). which can be extracted by automatic means.S. Ponzetto and M. Strube. 2007. "Deriving a large scale taxonomy from Wikipedia" . Proc. of the 22nd Conference on the Advancement of Artificial Intelligence, Vancouver, B.C., Canada, pp. 1440–1445. , it has been shown that a manually-constructed taxonomy, such as that of computational lexicons like WordNet, can be used to improve and restructure the Wikipedia category taxonomy.S. Ponzetto, R. Navigli. 2009. "Large-Scale Taxonomy Mapping for Restructuring and Integrating Wikipedia". Proc. of the 21st International Joint Conference on Artificial Intelligence (IJCAI 2009), Pasadena, California, pp. 2083–2088.
In a broader sense, taxonomy also applies to relationship schemes other than parent-child hierarchies, such as network structures. Taxonomies may then include a single child with multi-parents, for example, "Car" might appear with both parents "Vehicle" and "Steel Mechanisms"; to some however, this merely means that 'car' is a part of several different taxonomies.Jackson, Joab. "Taxonomy's not just design, it's an art," Government Computer News (Washington, D.C.). September 2, 2004. A taxonomy might also simply be organization of kinds of things into groups, or an alphabetical list; here, however, the term vocabulary is more appropriate. In current usage within knowledge management, taxonomies are considered narrower than ontologies since ontologies apply a larger variety of relation types.Suryanto, Hendra and Paul Compton. "Learning classification taxonomies from a classification knowledge based system." University of Karlsruhe; "Defining 'Taxonomy'," Straights Knowledge website.
Mathematically, a hierarchical taxonomy is a tree structure of classifications for a given set of objects. It is also named containment hierarchy. At the top of this structure is a single classification, the root node, that applies to all objects. Nodes below this root are more specific classifications that apply to subsets of the total set of classified objects. The progress of reasoning proceeds from the general to the more specific.
By contrast, in the context of legal terminology, an open-ended contextual taxonomy is employed—a taxonomy holding only with respect to a specific context. In scenarios taken from the legal domain, a formal account of the open-texture of legal terms is modeled, which suggests varying notions of the "core" and "penumbra" of the meanings of a concept. The progress of reasoning proceeds from the specific to the more general.Grossi, Davide, Frank Dignum and John-Jules Charles Meyer. (2005). "Contextual Taxonomies" in Computational Logic in Multi-Agent Systems, pp. 33–51.
History Anthropologists have observed that taxonomies are generally embedded in local cultural and social systems, and serve various social functions. Perhaps the most well-known and influential study of folk taxonomies is Émile Durkheim's The Elementary Forms of Religious Life. A more recent treatment of folk taxonomies (including the results of several decades of empirical research) and the discussion of their relation to the scientific taxonomy can be found in Scott Atran's Cognitive Foundations of Natural History. Folk taxonomies of organisms have been found in large part to agree with scientific classification, at least for the larger and more obvious species, which means that it is not the case that folk taxonomies are based purely on utilitarian characteristics. p. 9
In the seventeenth century, the German mathematician and philosopher Gottfried Leibniz, following the work of the thirteenth-century Majorcan philosopher Ramon Llull on his Ars generalis ultima, a system for procedurally generating concepts by combining a fixed set of ideas, sought to develop an alphabet of human thought. Leibniz intended his characteristica universalis to be an "algebra" capable of expressing all conceptual thought. The concept of creating such a "universal language" was frequently examined in the 17th century, also notably by the English philosopher John Wilkins in his work An Essay towards a Real Character and a Philosophical Language (1668), from which the classification scheme in Roget's Thesaurus ultimately derives.
Taxonomy in various disciplines
Natural sciences
Taxonomy in biology encompasses the description, identification, nomenclature, and classification of organisms. Uses of taxonomy include: Alpha taxonomy, the description and basic classification of new species, subspecies, and other taxa Linnaean taxonomy, the original classification scheme of Carl Linnaeus rank-based scientific classification as opposed to clade-based classification Evolutionary taxonomy, traditional post-Darwinian hierarchical biological classification Numerical taxonomy, various taxonomic methods employing numeric algorithms Phenetics, system for ordering species based on overall similarity Phylogenetics, biological taxonomy based on putative ancestral descent of organisms Plant taxonomy Virus classification, taxonomic system for viruses Folk taxonomy, description and organization, by individuals or groups, of their own environments Nosology, classification of diseases Soil classification, systematic categorization of soils
Business and economics Uses of taxonomy in business and economics include: Corporate taxonomy, the hierarchical classification of entities of interest to an enterprise, organization or administration Economic taxonomy, a system of classification for economic activity Global Industry Classification Standard, an industry taxonomy developed by MSCI and Standard & Poor's (S&P) Industry Classification Benchmark, an industry classification taxonomy launched by Dow Jones and FTSE International Standard Industrial Classification (ISIC), a United Nations system for classifying economic data North American Industry Classification System (NAICS), used in Canada, Mexico, and the United States of America Pavitt's Taxonomy, classification of firms by their principal sources of innovation Standard Industrial Classification, a system for classifying industries by a four-digit code United Kingdom Standard Industrial Classification of Economic Activities, a Standard Industrial Classification by type of economic activity EU taxonomy for sustainable activities, a classification system established to clarify which investments are environmentally sustainable, in the context of the European Green Deal. Records management taxonomy, the representation of data, upon which the classification of unstructured content is based, within an organization. XBRL Taxonomy, eXtensible Business Reporting Language SRK taxonomy, in workplace user-interface design
Computing Software engineering Vegas et al. make a compelling case to advance the knowledge in the field of software engineering through the use of taxonomies. Similarly, Ore et al. provide a systematic methodology to approach taxonomy building in software engineering related topics.
Several taxonomies have been proposed in software testing research to classify techniques, tools, concepts and artifacts. The following are some example taxonomies: A taxonomy of model-based testing techniques A taxonomy of static-code analysis tools
Engström et al. suggest and evaluate the use of a taxonomy to bridge the communication between researchers and practitioners engaged in the area of software testing. They have also developed a web-based tool to facilitate and encourage the use of the taxonomy. The tool and its source code are available for public use.
Other uses of taxonomy in computing Flynn's taxonomy, a classification for instruction-level parallelism methods Folksonomy, classification based on user's tags Taxonomy for search engines, considered as a tool to improve relevance of search within a vertical domain ACM Computing Classification System, a subject classification system for computing devised by the Association for Computing Machinery
Education and academia Uses of taxonomy in education and academia include: Bloom's taxonomy, a standardized categorization of learning objectives in an educational context Classification of Instructional Programs, a taxonomy of academic disciplines at institutions of higher education in the United States Mathematics Subject Classification, an alphanumerical classification scheme based on the coverage of Mathematical Reviews and Zentralblatt MATH SOLO taxonomy, Structure of Observed Learning Outcome, proposed by Biggs and Collis Tax Contributor Roles Taxonomy, commonly known as CRediT, is a controlled vocabulary of types of contributions to scholarly research published in academic journals
Safety Uses of taxonomy in safety include: Safety taxonomy, a standardized set of terminologies used within the fields of safety and health care Human Factors Analysis and Classification System, a system to identify the human causes of an accident Swiss cheese model, a model used in risk analysis and risk management propounded by Dante Orlandella and James T. Reason A taxonomy of rail incidents in Confidential Incident Reporting & Analysis System (CIRAS)
Other taxonomies A Taxonomy of Office Chairs, a scholarly work that applies detailed taxonomic hierarchies to a specific furniture typology. Military taxonomy, a set of terms that describe various types of military operations and equipment Moys Classification Scheme, a subject classification for law devised by Elizabeth Moys
Taxonomy for the web Websites with a well designed taxonomy or hierarchy are easily understood by users, due to the possibility of users developing a mental model of the site structure.
Guidelines for writing taxonomy for the web include:
Mutually exclusive categories can be beneficial. If categories appear in several places, it is called cross-listing or polyhierarchical. The hierarchy will lose its value if cross-listing appears too often. Cross-listing often appears when working with ambiguous categories that fits more than one place.