5. The combining form PHREN/O means

The combining form PHREN/O means "mind" or "diaphragm". To determine the meaning of a medical combining form, you can break it down into its components. In this case, "PHREN/O" consists of the root "phren" and the combining vowel "o". The root "phren" is derived from the Greek word "phrēn" which means "mind" or "diaphragm". The combining vowel "o" is often used to connect the root to a suffix or other root. Therefore, when you encounter the combining form "PHREN/O" in medical terminology, you can associate it with the concept of the mind or the diaphragm.