Which combining form denotes the heart?

• A. Audi/o
• B. Acou/o
• C. Cardi/o
• D. Coron/o

Answer: (C)

In medical terminology, the combining form that denotes the heart is cardi/o. It comes from the Greek word for heart (kardia) and appears in terms like cardiology, cardiac, and cardiomegaly, all of which specifically relate to the heart itself. The other roots point to different concepts: audi/o or acou/o relate to hearing, not the heart; coron/o refers to the crown and is used in terms like coronary, which describes vessels encircling the heart rather than the heart as an organ.