Tantra means the continuum or the continuity that connects or is the nature common to samsara and nirvana. Tantra is the Buddha nature of the ground, the union of the view and meditation of the path, and the bodies and wisdom resulting from spiritual pactice and realization. Thus tantra actually means the ultimate nature of phenomenal existence, its esoteric meaning, which is Buddhahood. While the tantric teachings are the expressions of the ultimate state, dharmakaya, they are ordinarily apprehended through words, indications, and texts of esoteric practices. The transmission of teachings and the esoteric power that comes from the primordial Buddha through master to disciple is the basis of the tantric tradition.

The Nyingma tradition of sadhanas is passed down through two principle means. The karma, or long transmission whereby teachings are passed from the teacher to his disciple through the Mind Transmission between Buddhas, the Sign Transmission between knowledge holders (Vidyadharas) and the Aural Transmission in an unbroken lineage from the time of Garab Dorje, Manjushrimita, Guru Rinpoche, Vimalamitra and Nagajurna.

The other is the short Terma Transmission of revealed treasure teachings. The termas are tantric scriptures, many from the Outer Tantras but the majority from the Inner Tantras. Guru Rinpoche gave esoteric teachings and transmission of Vajrayana to hundreds of disciples, his main students being the Twenty Five Disciples who are the root incarnations of the masters of this day. He concealed thousands of Termas in many places for the benefit of future followers, including in the essential nature of mind of his realized disciples where they were appropriate for the times.

Many realized masters and incarnations of Guru Rinpoche and his Twenty Five Disciples are Tertöns, able to reveal these treasure teachings in the form of Mind Termas, direct realization, or Earth Treasures, dakini scripts recovered from secret places, and only able to be deciphered by the Tertön. As Tulku Thondup notes, 'Nyingma termas are not scriptures that are concealed in another realm or place as books and then rediscovered or brought back as the same physical text. Rather, they are discovered through the awakening of the teachings from the nature of minds of the realized disciples of Guru Rinpoche and others'.