Does anyone know a website where I can look up word parts for medical terminology, NOT whole words?

Prefixes, suffixes, word roots, latin roots, etymology, and terminology for comparing different parts of broken-down words. For example, what do the parts 'meth' 'pen' and 'icillin' mean to help understand how penicillin and methicillin relate or differ? Regular term dictionaries define the whole word, but I don't want a description of the drug, I want to analyze the name of the drug. Not just for drugs, but all medicine terms.