Which organ does the prefix "cardio-" refer to?

The prefix "cardio-" specifically refers to the heart. This prefix is derived from the Greek word "kardia," which directly translates to "heart." It is commonly used in medical terminology to describe conditions, procedures, or aspects relating to the heart, such as cardiology (the study of the heart), cardiovascular (pertaining to the heart and blood vessels), and cardiomyopathy (a disease of the heart muscle). Understanding this prefix is crucial for interpreting various medical terms associated with heart health.