WordNet

WordNet® is "a lexical database for the English language", which "was developed by the Cognitive Science Laboratory at Princeton University under the direction of Professor George A. Miller (Principal Investigator)."

Source: WordNet website 

• Glossary
• ABC - DEF - GHI - JKL - MNO - PQRS - TUV - WXYZ
• Themes
• Air Pollution
• Biodiversity
• Chemicals
• Climate change
• Consumer safety
• Disease prevention
• Energy
• Environment
• Food & Lifestyle
• Phthalates
• Radiation & EMF
• Risks of new technologies
• Sustainable development
• Publications A-Z
• AIDS
• Agriculture
• Alcohol
• Arctic Climate Change
• Arsenic
• Aspartame
• Biocides
• Biodiversity
• Biofuels
• Boron
• CO₂ Capture & Storage
• Chernobyl
• Climate Change
• DBP
• DINP-DIDP
• Dental Amalgams
• Desertification
• Diet & Nutrition
• Dioxins
• Ecosystem Change
• Electromagnetic Fields
• Endocrine Disruptors
• Energy Saving Lamps
• Energy Technologies
• Fisheries
• Fluoride
• Forests
• Forests & Energy
• Genetically Modified Crops
• Global Public Health Threats
• Indoor Air Quality
• Malaria
• Mercury
• Mercury in CFL
• Nanotechnologies
• Nitrogen Dioxide
• Non-human primates
• Ozone
• PCBs
• Particulate Matter
• Personal Music Players & Hearing
• Phthalates in school supplies
• Power lines
• Psychoactive Drugs
• Respiratory Diseases
• Static Fields
• Sunbeds & UV radiation
• Tobacco
• Tooth Whiteners
• Triclosan
• Tuberculosis
• Water Disinfectants
• Water Resources