UMLS
The Unified Medical Language System (UMLS) is a compendium of many controlled vocabularies in the biomedical sciences. It provides a mapping structure between these vocabularies and thus allows to translate between the various terminology systems; it may also be viewed as a comprehensive thesaurus and ontology of biomedical concepts. UMLS further provides facilities for natural language processing. It is intended to be used mainly by developers of systems in medical informatics.
UMLS consists of the following components:
Metathesaurus, the core database of the UMLS, a collection of concepts and terms from the various controlled vocabularies, and their relationships;
Semantic Network, a set of categories and relationships that are being used to classify and relate the entries in the Metathesaurus; ¸
SPECIALIST Lexicon, a database of lexicographic information for use in natural language processing;
a number of supporting software tools.
The UMLS was designed and is maintained by the US National Library of Medicine, is updated quarterly and may be used for free. The project was initiated in 1986 by Donald Lindberg, M.D., then Director of the Library of Medicine.