NCI Thesaurus
NCI Thesaurus is a public domain thesaurus of concepts about Cancer produced by the National Cancer Institute
Deep and complex (compared to most broad clinical vocabularies) implementing rich semantic interrelationships between the nodes of its taxonomies.
Evolved from the NCI Metathesaurus. (NCI Metathesaurus is based on the National Library of Medicine Unified Medical Language System (UMLS) Metathesaurus)