Which combining form means a nipple or resembling a nipple?

• A. Papill/o
• B. Ped/o
• C. Axill/o
• D. Gnath/o

Answer: (A)

Papill/o means nipple or nipple-like projection. The root papilla is a nipple, and using papill/o to form terms communicates that nipple-related meaning, as in papilloma (a nipple-shaped tumor) or papillitis (inflammation of a nipple-like projection). The other roots point to unrelated body parts: ped/o is foot, axill/o is armpit, and gnath/o is jaw. So papill/o is the correct combining form for "nipple or resembling a nipple."