Multilingual Glossary of Technical and Popular Medical Terms
Provides medical terms in English, French, Spanish, Portuguese, Italian, Dutch, Greek, Danish, and German.

Alcohol and Other Drug Thesaurus
National Institutes of Health thesaurus. Provides resource for medical, social, and demographic terms related to alcohol and drug use.

High Definition Dictionary
Mixed collection of drug terminology with an apparently arbitrarily selected mix of other, unrelated terms. Dictionary accepts contributions of new terms.