It's the origin of many English words related to the heart, such as:
* Cardiac: relating to the heart.
* Cardiologist: a doctor specializing in heart diseases.
* Cardiovascular: relating to the heart and blood vessels.
* Cardiopulmonary: relating to the heart and lungs.
While "kardia" specifically refers to the physical organ, it can also have a broader metaphorical meaning of "heart" in the sense of emotions, feelings, and spirit.