What does the suffix "-an" signify in medical terms?

The suffix "-an" is used in medical terminology to indicate a relationship or connection to a certain subject or field. When attached to a root word, it specifies that something pertains to or is characteristic of that root term. For instance, in terms like "vegetarian," the suffix signals a connection to vegetables or a lifestyle associated with plant-based foods. This tendency to indicate relationship helps categorize conditions, characteristics, or classifications within medical and scientific contexts.

In this case, the other options do not correctly represent the function of the suffix. "With," "without," and "excessive" imply the presence, absence, or degree of something rather than the relationship that "-an" establishes with the root term. Hence, the correct choice signifies a direct link to a particular quality or attribute designated by the root.