What does the prefix "eso-" signify in medical terminology?

The prefix "eso-" in medical terminology derives from the Greek word "esō," meaning "inside" or "within." This implies that "eso-" is used to indicate something that is inward or internal in nature. For example, it appears in terms like "esophagus," which is the tube that carries food from the throat to the stomach, implying it is located internally within the body. Understanding the meaning of this prefix helps in deciphering various medical terms related to internal structures or conditions.

The other options do not accurately represent the meaning of "eso-." While "outward," "outside of," and "normal" have their own distinct meanings in medical terminology, they do not relate to the concept of being inward or internal, which is what "eso-" specifically conveys.