Which prefix signifies something is 'under' or 'below'?

The prefix that signifies something is 'under' or 'below' is "infer-." This prefix comes from the Latin word "inferus," meaning lower or beneath. In medical terminology, it is commonly used in terms such as "inferior," which refers to a structure that is situated below another, or has a lower position in relation to another part of the body.

The other prefixes provided convey different meanings: "extra-" means outside or beyond, "exo-" relates to something externally or outside, and "ep-" indicates something that is upon or above. Understanding these distinctions is vital for interpreting medical terms accurately, as the prefixes provide essential context about the location or relationship of structures in anatomy and healthcare.