What is the primary meaning of the prefix "epi-"?

The prefix "epi-" primarily means "above" or "upon." This prefix is derived from Greek, where it conveys a sense of position that suggests something is situated on top of or in addition to something else. In medical terminology, it is commonly used in words like "epidermis," which refers to the outer layer of skin (above the dermis), and "epicardium," indicating the membrane on the surface of the heart (upon the heart).

Understanding this prefix is essential in deciphering medical terms, as it provides context about location and position relative to other structures in the body. The other options convey different concepts that do not align with the meaning of "epi-." For instance, "apart" does not suggest a positional relationship, "without" implies the absence of something, and "outward" indicates direction rather than position. Thus, the choice of "above" is accurately aligned with the definition of the prefix.