Which prefix is used to indicate being above something?

The prefix "epi-" is derived from the Greek word 'epí,' which means 'upon' or 'above.' This prefix is often used in medical terminology to indicate a position that is over or on top of something. For example, in the term "epidermis," which refers to the outer layer of skin that sits above the deeper layers.

Understanding the meaning of "epi-" helps to clarify its usage in various medical contexts, where spatial relationships or anatomical positions need to be described. In contrast to the other prefixes provided, "dys-" denotes difficulty or abnormality; "di-" refers to two or double; and "circum-" means around. These meanings do not convey the concept of being above or upon something, which is why "epi-" is the correct choice for this question.