What is the best definition for this combination word parts derm and logy?

The combination of the Word parts "derm" and "logy" forms the term "dermatology." "Derm" refers to the skin, while "logy" comes from the Greek "logia," meaning "study of." Therefore, dermatology is defined as the study of the skin and its diseases. It encompasses various aspects of skin health, including diagnosis, treatment, and prevention of skin conditions.