CancerWEB's On-line Medical Dictionary is a great resource
for simple medical term/condition look-ups and is not restricted to cancer
at all. Some terms are not in the dictionary but it is pretty good for
all that. This is the medical dictionary that I use.
Part of Health Central's online pharmacy. An extensive range of drugs
with monographs on each one plus patient information. A "fuzzy" search
engine means that you never get back just one drug which is great if you're
not entirely sure of the spelling but slightly irritating if you are. There's
a lot of great stuff here but it's tricky to get at it.