Online Medical Dictionary

stack of medical books

When you need medical information but not necessarily medical advice, an online medical dictionary may be able to answer your questions without the cost associated with a doctor's office visit. Fortunately, you have several to choose from. Here are just a few:

KMLE Medical Dictionary

The KMLE Medical Dictionary is a medical dictionary search engine which searches American Heritage Stedman's Medical Dictionary, MeSH, Taber's Medical Dictionary, Merrian-Webster's Medical Dictionary, Dorland's Illustrated Medical Dictionary, CancerWeb Medical Dictionary, Merrian-Webster's Medical Dictionary, Medical Dictionary, WHO ICD-10 Version 2006, American Heritage Dictionary, and a number of other resources.

National Institutes of Health

The National Institutes of Health offers an online medical dictionary. The site is good for the lay person, because it allows you to do wild card searches using an asterisk. This means that if you do not know the correct spelling of a medical term, you can still search for the correct spelling and meaning. The site even contains a brief tutorial so that can learn your way around medical terminology. There are also lists of common abbreviations and what parts of words mean.

Medline Plus Dictionary

The Medline Plus Medical Dictionary is just one feature available through the National Library of Medicine, the world's largest medical library. Besides a free online medical dictionary, visitors can find information about:

  • 700 diseases and conditions
  • Listing of hospitals and physicians
  • Medical encyclopedia
  • Prescription and nonprescription drugs
  • Links to clinical trials

Much of the information at Medline is available in both English and Spanish.

MedTerms Dictionary

The MedTerms Medical Dictionary is a product of, an online healthcare media publishing company. The goal of is to provide in-depth, easy-to-read, and authoritative medical information to the average consumer. is also the author of Webster's New World Medical Dictionary First and Second Editions.

The MedTerms Dictionary provides the definitions to more than 16,000 medical terms. These terms can be looked up using a quick search box or you can use an extensive alphabetical listing to look up hard-to-spell and often-misspelled terms. The website also offers the following features:

  • Quick browse for information about medical conditions
  • Medical news
  • Symptoms and signs term search
  • Information on common procedures and tests
  • Details about diseases and conditions
  • Relevant information about 2,500 medications

Dorland's Illustrated Medical Dictionary

The name Dorland is probably best know for the publication of the American Pocket Dictionary and the American Illustrated Medical Dictionary. Now they have brought this same knowledge to you via an illustrated online medical dictionary. Unfortunately, this dictionary is not available to just anyone. You need a passcode that is only available with the purchase of one of their printed dictionaries.

Alternatives To An Online Dictionary for Science and Medicine

If you cannot find the information you want in online dictionaries, don't give up your search. Try one of the following solutions:

  • Look for support groups specializing in the medical condition you are researching. Often support group websites offer a large database of medical-related articles and forums where you can ask questions.
  • Ask your local pharmacist.
  • Look in the phone book in your area for Ask-a-Nurse or the equivalent free community service.
  • Contact a local medical school.
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