Medical Online Dictionaries

When you read or write an article on medicine, you may occasionally need to check the meaning of an unknown term in the dictionary. Sadly, regular dictionaries do not contain all medical terms and abbreviations. So do you know where to look?

Here, we introduce three of the most well-known and useful online medical dictionaries in English which you can consult for free.

Merriam-Webster’s Medical Dictionary


This is arguably one of the most comprehensive free medical dictionary online. Based on the description on the homepage, this dictionary provides up-to-date definitions for medical terms and abbreviations. You can either search a word/phrase or manually browse it in alphabetically ordered lists. Also, on the right, you see a box depicting the Word of the Day, along with its definition and pronunciation. Below, you can find lexical games as well as posts and videos on terminology and etymology, among other things.

When you look up a medical term, this dictionary offers you the definition, pronunciation (both in phonetic symbols and audio), examples of the word being used in sentences (along with the name of the source from which the sentences were taken), and the history and etymology of the word (if available). Moreover, it offers information on when the word was first used, how popular it is in terms of being searched, words rhyming with it, and comments posted by users on the word. You can also share the word on social media by clicking on the respective icons.

Last, but not least, this dictionary offers a very handy thesaurus, listing the words that go with the word you have searched, its synonyms, and antonyms, if any.

The Free Dictionary’s Medical Dictionary

The Free Dictionary is one of the largest and most expansive online dictionaries, offering a variety of dictionaries on various disciplines, including medicine. Based on the description of its medical dictionary, its main sources are the second edition of the American Heritage® Stedman’s Medical Dictionary and Dorland’s Medical Dictionary for Health Care Consumers. It also draws from The Gale Encyclopedia of Medicine, Mosby’s Dictionary of Complementary and Alternative Medicine and Saunders Comprehensive Veterinary Dictionary.

The home page offers a column on the left, depicting live searches, that is, the words that are currently being searched by others. In addition to this, you can read the most popular definitions and relevant articles on the home page.

This dictionary is also available as a mobile or desktop app for various platforms, all of which available to download from the homepage.

When you search a word, this website offers you the definition from the sources mentioned above, pronunciation (phonetic and audio), links to relevant pages on Wikipedia, and a link to the page so that you can share the word with your friends. If the word you have searched is the name of a disease, you can also find information on its diagnosis and treatment, along with a patient discussion section.

This dictionary also offers links to questionnaires and scales related to the word (if available), examples of the word being used in context, and a list of relevant words.

WebMD's Medical Dictionary

WebMD is a leading website on medicine. Its dictionary, however, if not a conventional medical dictionary. It is very concise, only including words absolutely relevant to the domain of medicine, such as the names of drugs and procedures. You can find to-the-point definitions/explanations for the searched term as well as tools for saving it or sharing it with others, but that’s it. There is no thesaurus, usage examples, etymology section, or the like. Still, it is a very handy tool, especially if you are in a rush.