Terms and definitions needed when one study happiness

In order to understand better my following posts, i decided to start by defining few terms that i will use more frequently, and are close to each other.

Kindness - behavior that involve being friendly, generous or considerate;

Pro-social - term favored by scientists to refer to kindness;

Compassion - literally means "suffer together", it is a feeling that arises when you witness another's suffering and feel motivated to help relieve that suffering;

Empathy - ability to sense on imagine other people's emotions;

Sympathy - means "feel together", feeling close to other's emotions, but without the urge to help as in the case of compassion;

Pity - feeling sorry for someone's suffering, but the observer occupies a place of superiority and look down to the one suffering, while in the case of compassion they are equals.