Art and Architecture Thesaurus
- Getty's terms, as used in several AAT indexes.
- http://www.getty.edu/research/conducting_research/vocabularies/aat/

Inter Active Terminology for Europe (IATE)
- European Union terminology. Available on most European Union languages.
- http://iate.europa.eu/iatediff/

Getty Thesaurus of Geographic Names
- Structured vocabulary of place names.
- http://www.getty.edu/research/conducting_research/vocabularies/tgn/

Thesaurus of Musical Instruments
- Over a thousand instruments, with relational links based on the Library of Congress Subject Headings.
- http://alteriseculo.com/instruments/

The Astronomy Thesaurus
- Astronomical terms. Searches may be performed in English, French, German, Italian, and Spanish.
- http://www.mso.anu.edu.au/library/thesaurus/

Concept Space
- Management education thesaurus from the London Business School organizes terms into a solar system of related ideas.
- http://conceptspace.london.edu/

Alcohol and Other Drug Thesaurus - AOD
- National Institutes of Health thesaurus. Provides resource for medical, social, and demographic terms related to alcohol and drug use.
- http://etoh.niaaa.nih.gov/AODVol1/Aodthome.htm

Library of Congress Classification Schedules
- A comprehensive list of LOC Classification schedules.
- http://www.loc.gov/catdir/cpso/lcco/lcco.html

Library of Congress Thesauri
- Links to multiple LOC thesauri, including GLIN, the Global Legal Information Network.
- http://www.loc.gov/lexico/servlet/lexico

Babynames Thesaurus
- You can search for a name from its meanings. The site has more than 10,000 names with meanings.
- http://www.yourbabysname.com/thesaurus.htm

Maths Thesaurus
- Definitions of common mathematical terms, along with broader, narrower, and related concepts.
- http://thesaurus.maths.org/

NASA Thesaurus
- National Aeronautics and Space Administration Thesaurus. Extensive coverage of scientific terms.
- http://www.sti.nasa.gov/nasa-thesaurus.html