Many disciplines have specialist dictionaries and encyclopedias - reference material which can provide you with a definitive explanation of core information and concepts in medicine and health.
Medpedia is a wiki project which aims to provide a collaborative reference resource for medical information.
This is the US National Library of Medicine's source of health information for patients and their families.
Better Health Channel
Provided by the Victorian State Government, this is an excellent source of patient level health information.
Pogofrog is an internet search engine which delivers largely medically oriented results.
These resources are designed for patients. The level of information is appropriate for people without health qualifications.
These resources provide information to support carers.