What is the combining form meaning 'heart'?

• A. Gast/o
• B. Pulmon/o
• C. Nephr/o
• D. Cardi/o

Answer: (D)

Identifying medical combining forms for body parts helps you decode terms like cardiology or cardiogram. The combining form meaning heart is cardi/o. It comes from the Greek word kardia for heart, and the o acts as a linking vowel to attach suffixes or other word parts, as in cardiology, cardiovascular, or cardiogram. The other forms point to different organs: gast/o refers to the stomach (gastric, gastrectomy), pulmon/o to the lungs (pulmonary, pulmonology), and nephr/o to the kidneys (nephrology, nephritis). So cardi/o is the correct root for heart.