Final answer:
The term for a fatty mass is 'lipoma,' which is made up of adipose tissue characterized by adipocytes specialized in lipid storage.
Step-by-step explanation:
The term that means a fatty mass is D. lipoma. A lipoma is a type of growth made up of adipose tissue, which is specialized connective tissue composed mainly of fat-storage cells called adipocytes. These cells are specialized for lipid storage and can accumulate in various tissues, including subcutaneous tissue. In contrast, adiposis (A) generally refers to the state of having excessive fat, lipectomy (B) is a surgical procedure to remove fatty tissue, and adipopathy (C) pertains to a disease of the adipose tissue.