A bhikkhunī or bhikṣuṇī is a fully ordained female monastic in Buddhism. Male monastics are called bhikkhus. Both bhikkhunis and bhikkhus live by the Vinaya, a set of rules. Until recently, the lineages of female monastics only remained in Mahayana Buddhism and thus are prevalent in countries such as China, Korea, Taiwan and Vietnam but a few women have taken the full monastic vows in the Theravada and Vajrayana schools over the last decade. .
Buddhist monasticism is one of the earliest surviving forms of organized monasticism and one of the fundamental institutions of Buddhism. Monks and nuns, called bhikkhu and bhikkhuni, are responsible for the preservation and dissemination of the Buddha's teaching and the guidance of Buddhist lay people. Three surviving traditions of monastic discipline (Vinaya), govern modern monastic life in different regional traditions: - the Theravada in Southeast Asia and Sri Lanka - the Dharmaguptaka in East Asia - .