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

The prefix "A-" in medical terminology signifies the absence or lack of something. It is commonly used to indicate a condition where a particular element is missing, such as "aseptic," which means without infection, or "apnea," meaning without breath. This helps in conveying specific medical conditions that are characterized by a deficiency or the complete absence of normal bodily functions or features. Understanding this prefix is crucial in the medical field, as it provides essential context for various terms related to health and disease.

The other choices represent different prefixes or meanings that do not align with the definition of "A-" in this context, clarifying that "A-" specifically pinpoints lack or absence.