What is the meaning of the prefix "ad-"?

The prefix "ad-" originates from Latin, meaning "to" or "toward." This prefix is commonly used in medical terminology to indicate direction or movement toward a specific structure or area in the body. For example, the term "adrenal" refers to the glands located near the kidneys, effectively meaning "toward the kidneys."

In contrast, the other options have distinct meanings that are not aligned with the definition of "ad-." The prefix meaning "away from" represents a separate concept, while "up, toward" may imply a directional orientation but is not equivalent to "ad-." The term "before" pertains to a temporal or sequential context, which is also not related to the meaning of "ad-." Hence, "C. Toward" captures the essence of the prefix accurately within the context of medical terminology.