What does the prefix "a, an" indicate in medical terms?

In medical terminology, the prefix "a" or "an" signifies the absence or lack of something. For instance, in terms like "aseptic," it indicates the absence of infection or pathogens. Similarly, "anemia" refers to the lack of sufficient red blood cells or hemoglobin in the blood. This prefix functions as a negation, effectively conveying a meaning of "without" or "not," which is essential for understanding various medical conditions and terms.

The other options focus on different prepositions that convey distinct meanings unrelated to the absence or lack of something. Thus, understanding that "a, an" implies "without" strengthens comprehension of how these prefixes modify the meaning of medical terms.