Online Science Dictionary

Besides the following dictionaries, you should consider looking at some of the resources in our Online Latin Dictionary article. Science terminology is often based on Latin, sometimes Greek, so understanding the Latin roots can often help you figure out what words mean.

Online Science Dictionary Options

Online Biology Dictionaries

Though they're difficult to find, there are dozens of online biology dictionaries and encyclopedias, some more updated than others. For a good microbiology and evolution reference, try ISCID's Online Encyclopedia of Science and Philosophy, a wiki that's just been released as a beta. It's easy to research and clearly written, with short entries that are somewhere between encyclopedic and dictionary-ish. One of the best science dictionaries is KMLE Medical Dictionary which allows searching through multiple medical/biology dictionaries.

A very good online science dictionary is the University of Texas's Biotech Dictionary. It's extremely complete, and each entry is nicely cross-referenced with hypertext, so it's easy to do the research you need.

Online Chemistry Dictionaries

Good chemistry dictionaries are a little harder to find; most are on the incomplete side. There are a few really good ones, though. With an extensive dictionary as well as a periodic table and chemistry tools, ChemiCool has a goofy name but great resources.

Kilcoyne's Chemistry Glossary is also reasonably complete, though it lacks the extra tools some other sites provide.

A really fun online science dictionary is the Glossary of Archaic Chemical Terms. This dictionary lists archaic terminology for chemicals and chemical actions we know by different names today.

Online Physics and Math Dictionaries

Though it's a little elementary, the Light and Matter physics glossary has links to good online textbooks for a better depth of knowledge. Another good place is the Physics Dictionary at Feimer's Physics Page. Most physics dictionaries online are specialty dictionaries, and a good reference for finding specialty dictionaries is the AlphaDictionary Physics section.

Possibly the best math dictionary online is Mathwords, which covers terminology from algebra to calculus. It's very complete and includes diagrams where appropriate. Another excellent online math dictionary is the PRIME dictionary, which includes more elementary and more advanced topics than Mathwords. PRIME is also much harder to navigate and not quite as complete or thorough.