NCI Metathesaurus (NCIm) is a wide-ranging biomedical terminology database that covers most terminologies used by
NCI for clinical care, translational and basic research, and public information and administrative activities.
NCIm contains most public domain terminologies from the National Library of Medicine's
as well as many other biomedical terminologies created by or of interest to NCI and its partners. Some propriety
terminologies are included, with permission, and have restrictions on their use
The current version of the NCI Metathesaurus, based on the UMLS build 2015AB,
covers up to National Cancer Institute Thesaurus, 16.04d. A viewer for the UMLS changes document can be downloaded from
- Maps 4,000,000 terms from more than 75 sources into 2,000,000 biomedical concepts that represent their meaning.
- Displays preferred terms, synonyms, definitions, and other information from each source.
- Links to
and other related information sources.
- Contains 22,000,000 cross-links between content elements.
- Updated frequently by a team of biomedical terminology and subject matter experts.