MedLinePlus Medical Dictionary
http://www.nlm.nih.gov/medlineplus/mplusdictionary.html
On-Line Medical Dictionary
http://cancerweb.ncl.ac.uk/omd/
MedBioWorld
http://www.sciencekomm.at/advice/dict.html
Google Subdirectory
http://directory.google.com/Top/Reference/Dictionaries/By_Subject/Medicine/?il=1
