This is a useful glossary of HIV/AIDS-related terms and definitions. The glossary is intended mainly for U.S. general public and healthcare providers. The resource is maintained by the U.S. Department of Health and Human Services (DHHS). http://www.aidsinfo.nih.gov/Glossary/GlossaryDefaultCenterPage.aspx?MenuItem=AIDSinfoTools

This well-known dictionary includes basic (keyword) and advanced search engines. http://www.nlm.nih.gov/medlineplus/mplusdictionary.html

This is an annotated list of words and phrases related to the development of an HIV vaccine. It is maintained by the National Institute of Allergy and Infectious Diseases, U.S. http://www.thebody.com/content/art6531.html

This site defines terms in 6000 rare diseases. A rare (or orphan) disease is generally considered to have a prevalence of fewer than 200,000 affected individuals in the United States. Access is via clicking on the link titled 'Current Rare Diseases and Synonyms.' The site is maintained by the Office of Rare Diseases, National Institutes of Health, U.S.  See link to 'Rare Disease Terms' from initial page of website.  http://rarediseases.info.nih.gov/RareDiseaseList.aspx