Unlike ordinary definitions of this concept which generally involve attachment of one sort or another, in Buddhism it means an unselfish interest in and commitment to another's welfare.
Is the desire that others be free from suffeing and involves the capacity to feel wiht another and to feel the urge to help
Is spontaneous happiness at another's good fortune. It rests on the recognition that all sentient beings are capable of bliss as all can become Buddhas
Is not to distinguish between friend, enemy or stranger, but to regard evry sentient being as equal. It involves clear-mindedness, and tranquility. Its opposite is indifference