The four Brahma Vihàras are considered by Buddhism to be the four highest emotions. The word brahma literally means `highest' or `superior'. It is also the name given to the supreme god in Brahmanism during the Buddha's time. Vihàra means `dwelling', `living' or `abiding'. Thus the Brahma Vihàras are not emotions one occasionally feels, but those that one `lives in' and `lives by' all the time. The four Brahma Vihàras are love, compassion, sympathetic joy and equanimity. They can be understood from several different perspectives.
The Visuddhimagga saw them as four related but separate states and equating each with the feelings and attitude a mother might have towards her four sons `...one an infant, one an invalid, another in the prime of youth and a fourth successfully making his way in the world. She wants the infant to grow up, the invalid to recover, the one in the prime of youth to long enjoy his youth and she has no worries about the one making his way in the world'(Vism. IX,108). Alternatively, they could be seen as skillful and kindly ways of relating to others according to their situation; relating to friendly people with love, to those in distress with compassion, to the successful with sympathetic joy and to unpleasant people with equanimity.
The purpose of the practice called loving-kindness meditation is to encourage and nurture the Brahma Vihàras. See Kindness and Sympathy.