Which term means sleep?

• A. Sonic
• B. Sono
• C. Somn(e)
• D. Somat(o)

Answer: (C)

The concept being tested is recognizing medical word roots that indicate sleep. The sleep root is somn- (often seen as somn/o or somn/e when forming terms). So terms built with somn- carry the meaning related to sleep, as in somnolence (drowsiness), somniferous (sleep-inducing), or somnambulist (someone who walks in sleep). The other roots here refer to different ideas: sonic or sono relates to sound, and somat- relates to the body. Therefore, the form using somn- is the correct one to mean sleep.