Empathy refers to identification with or sharing of another's feelings , situation, or attitudes nad ist the attribution of one's personal feelings or attitudes to an external object. Likewise it is the vicarious experience of another's feelings; putting oneself in another's shoes.
Empathy refers to the ability to put oneself in the shoes of another person-to experience events and emotions (e.g., joy and sadness) the way that person experiences them. Likewise, it is the ability to understand how only people are feeling and to identify with the likely emotions. Developing empathy involves several processes: recognizing the emotional state of another person; perspective taking; having a similar emotional response; and acting on it (e.g., expressing sympathy).
Other /More definition:
Empathy refers to the ability to understand someone else's point of view, and to share their emotions.
List of books: Empathy