Karuna (originally a Pali word; also regarded as a Sanskrit word) is the Jainist concept of love. It is also translated as "compassion," a key concept of MahayanaBuddhism (see Bodhisattva and Avalokitesvara). As mercy, it is the special kindness shown to those who suffer. It is considered the indispensable complement to enlightened wisdom or Prajña. Compassion is important in all schools of Buddhism.
Karuna is commonly summed up as wisdom tempered with compassion.