* Concrete noun: When referring to the physical organ, it is a concrete noun.
* Example: "The doctor examined the patient's heart."
* Abstract noun: When referring to emotions, feelings, or the core of something, it becomes an abstract noun.
* Example: "She had a kind heart." (Here, "heart" represents kindness, an abstract concept)
* Example: "The heart of the city is bustling with life." (Here, "heart" represents the central part, an abstract concept)