Here is a list of online medical dictionaries.

Add more with the following format:

==The name of the Medical Dictionary==
short introduction
*Language: language
*Terms: the number of terms the dictionary contains
*Alphabetical listing: yes/no
*Search: yes/no
*Search with wildcard asterisk: yes/no
*Link: address of the dictionary
*Other: other features

 MedTerms.com
MedTerms medical dictionary is the medical reference for MedicineNet.com. 
Language: English
Terms: 16,000
Alphabetical listing: yes
Search: yes
Search with wildcard asterisk: yes
Link: http://www.medterms.com/script/main/hp.asp
 Medical Dictionary (the Free Dictionary)
The main sources of TheFreeDictionary's Medical dictionary are The American Heritage® Stedman's Medical Dictionary, Second Edition and Dorland's Medical Dictionary for Health Care Consumers. The Medical dictionary also draws from 
The Gale Encyclopedia of Medicine,Second Edition and Mosby's Dental Dictionary, Second Edition, Mosby's Dictionary of Complementary and Alternative Medicine, Sauuders Comprehensive Veterinary Dictionary, 3rd.
Language: English
Terms:
Search: yes
Link: http://medical-dictionary.thefreedictionary.com/
 Stedman's Medical Dictionary (medilexicon.com)
Stedman's Medical Dictionary(2006) Lippincott Williams Wilkins.
Language: English
Terms: 100,000+
Alphabetical listing: yes
Search: yes (fulltext and title)
Search with wildcard asterisk: yes(fuzzy search)
Link: http://www.medilexicon.com/medicaldictionary.php
Useful link:
Stedman's http://www.stedmans.com