Science

Dyer Labs Technical Resource Glossaries
Specialized multi-language technical glossaries for optical microscopy, firearms and a general glossary of abbreviations.
http://www.dyerlabs.com/glossary/

FDA Pesticide Glossary
Glossary of alternative names for pesticides and related chemicals in PDF format.
http://vm.cfsan.fda.gov/~frf/pestglos.html

Glossary for Transport Statistics, 3rd edition
Road, rail, waterways, and pipelines. Also in print, with parallel versions in French and Russian. By the United Nations Economic Commission for Europe (UN/ECE), the European Conference of Ministers of Transport (ECMT), and Eurostat, 2003, 109 pages. [PDF]
http://www1.oecd.org/cem/online/glossaries/GloStat3e.pdf

A Glossary of Color Science
Organized by Alex Byrne and David Hilbert.
http://tigger.uic.edu/~hilbert/Glossary.html

Linguistic Glossary
This is a glossary of terms used in the morphological, syntactic, and pragmatic analysis of text.
http://www.sil.org/linguistics/GlossaryOfLinguisticTerms/

Metallurgical Dictionary
Searchable dictionary of more than 1,000 metallurgical terms.
http://www.principalmetals.com/glossary/step1.asp

Stammtisch Beau Fleuve
Glossary of 2,000 science and technology related terms with a healthy mix of other hard-to-categorize references.
http://www.plexoft.com/SBF/