NASA Thesaurus

The NASA Thesaurus contains the authorized NASA subject terms used to index and retrieve materials in the NASA Technical Reports Server (NTRS). The scope of this controlled vocabulary includes not only aerospace engineering, but all supporting areas of engineering and physics, the natural space sciences (astronomy, astrophysics, and planetary science), Earth sciences, and the biological sciences. The NASA Thesaurus contains over 18,400 subject terms, 4,300 definitions, and more than 4,500 USE cross references.

If you have any questions or would like to discuss your usage of the thesaurus with the STI Program Office, contact the STI Information Desk.

Please cite the NASA STI Program in your work if you incorporate/use the NASA Thesaurus. You may copy and paste any one of the standard citations below (be sure to change ‘SKOS’ to the file format you used):

  • APA
    NASA STI Program. (2012). NASA thesaurus [Data file]. Retrieved from
  • MLA
    NASA STI Program. NASA Thesaurus. Washington, DC: National Aeronautics and Space Administration, 2012. SKOS.
  • Chicago
    NASA STI Program. NASA Thesaurus. SKOS. Washington, DC: National Aeronautics and Space Administration, 2012.

Choose the file format you would like to use:

  • PDF Version
    Access the PDF version (updated January 2012) using the links below:

  • NASA Thesaurus Data File
    The NASA Thesaurus Data File contains all valid terms and hierarchical relationships, USE references, and related terms in machine-readable form. The Data File is available in the following formats: RDF/SKOS, RDF/OWL, ZThes-1.0, and CSV/TXT.

    The full NASA Thesaurus data files can be downloaded by clicking on a link below.