Medical terms are overwhelmingly derived from either Latin or Greek word parts. Each medical term will have one or more root words or stems. These root words are the main meaning of the word.
The medical term may have one or more prefixes or suffixes to describe the medical term. In addition, a medical term may have a vowel to help with pronunciation between the word parts.
When you combine the parts of a medical term, each part's meaning always stays the same. For example, the root word "derm" means skin in medical terminology. Any time you see the root "derm" in a word, you will know that it has something to do with your skin, such as dermatology, dermatitis and dermabrasion.
There are thousands of medical root words, but here are a few of the more common ones and their definitions. "Myo" means muscle and "cardio" means heart; "myocardial" means heart muscle. "Vascular" means blood vessels; "cardiovascular" refers to the heart's blood vessels.
Prefixes and suffixes further define the medical root term. For example, "-itis" means inflammation, therefore "dermatitis" means inflammation of the skin. The suffix "-ology" refers to the study of a science; therefore "cardiology" would mean the study of the heart.