Which prefix indicates a position that is around something?

The prefix that indicates a position that is around something is "peri-." This prefix is derived from the Greek word meaning "around" or "surrounding." It is commonly used in medical terminology to describe structures or conditions that exist in proximity to or encircle another structure. For example, "pericardium" refers to the membrane that surrounds the heart.

In contrast, the other prefixes have different meanings that do not imply the concept of being "around." "Super-" indicates something that is above or excessive, "endo-" refers to inside or within, and "exo-" means outside or external. Each of these prefixes conveys a distinct relative position, but only "peri-" accurately represents the idea of surrounding or encircling something.