An international knowledge classification system used in libraries and bibliographic services.
Overview
Universal Decimal Classification
The Universal Decimal Classification (UDC) is a multilingual classification system for libraries and bibliographic services, developed in 1895 by Paul Otlet and Henri La Fontaine in Belgium. Built upon and improved from Melvil Dewey's Decimal Classification, it is currently used in approximately 150,000 libraries across more than 130 countries worldwide. The system consists of 10 main classes (0-9) and has been translated into over 40 languages, making it one of the most internationally widespread classification systems.
library
classification
knowledge organization
bibliographic
international standard
| code | slug | name | description |
|---|---|---|---|
| 0 | science-knowledge-information | Science and Knowledge. Organization. Computer Science. Information. Documentation. Librarianship. Institutions. Publications | Covers science, knowledge organization, computer science, information, documentation, librarianship, institutions, and publications. |
| 1 | philosophy-psychology | Philosophy. Psychology | Covers philosophy, metaphysics, logic, ethics, and psychology. |
| 2 | religion-theology | Religion. Theology | Covers religion, theology, mythology, and religious practices. |
| 3 | social-sciences | Social Sciences | Covers sociology, political science, economics, law, public administration, and education. |
| 4 | vacant | (Vacant) | A vacant class reserved for future expansion. |
| 5 | mathematics-natural-sciences | Mathematics and Natural Sciences | Covers mathematics, astronomy, physics, chemistry, earth sciences, and biology. |
| 6 | applied-sciences-medicine-technology | Applied Sciences. Medicine. Technology | Covers medicine, engineering, agriculture, home economics, management, and chemical technology. |
| 7 | arts-recreation-entertainment-sport | The Arts. Recreation. Entertainment. Sport | Covers fine arts, music, theater, film, recreation, entertainment, and sports. |
| 8 | language-linguistics-literature | Language. Linguistics. Literature | Covers linguistics, languages, literature, and literary criticism. |
| 9 | geography-biography-history | Geography. Biography. History | Covers geography, biography, archaeology, and history. |