Cardiac/ˈkɑːrdiæk/ Definition 1 of 2Pro Tip 1/3Medical Context Use 'cardiac' mainly in medical or health-related discussions. The doctor discussed the patient's cardiac health during the check-up. Pro Tip 2/3Emergency Situations Often used to describe emergencies involving the heart. The paramedics responded quickly to the cardiac arrest call. Pro Tip 3/3Technical Jargon 'Cardiac' signals technical vocabulary, best understood by healthcare professionals. Cardiac output is a term often used by cardiologists.