Sanskrit for "continuum" or "unbroken stream." from Sanskrit tantram, lit. "loom, warp," hence "groundwork, system, doctrine," from tan "to stretch, extend." Tantra refers first (1) to the continuum of vital energy that sustains all existence, and second (2) to the class of knowledge and practices that harnesses that vital energy, thereby transforming the practitioner. There are many schools of Tantra, but they can be classified in three types: White, Grey and Black. Tantra has long been known in the West as Alchemy. In Asian religions, there is a corresponding class of books called Tantras.
“In the view of Tantra, the body's vital energies are the vehicles of the mind. When the vital energies are pure and subtle, one's state of mind will be accordingly affected. By transforming these bodily energies we transform the state of Consciousness.” -The 14th Dalai Lama