What does the prefix "sub-" mean?

The prefix "sub-" originates from Latin, meaning "under," "below," or "less than." This prefix is commonly used in medical terminology to indicate a position that is lower than or beneath something else. For example, in the term "subcutaneous," "sub-" specifies that something is located under the skin. This prefix can also imply a lesser degree or amount, as seen in terms like "subnormal," which denotes a condition that is below the normal range. Understanding this prefix is crucial for interpreting various medical terms accurately.