Final answer:
The combining form pil/o in the term pilonidal means hair.
Step-by-step explanation:
Pilonidal refers to a condition that involves a cyst or abscess occurring in the natal cleft of the buttocks. It is typically caused by hair follicles becoming blocked and infected, leading to the formation of a painful bump or sore.
Therefore Pilonidal refers to a condition involving a cyst or abscess in the buttocks caused by blocked and infected hair follicles. In the term pilonidal, the combining form pil/o means hair.