2.  Sanskrit for "System" or "Doctrine." Tantra is a very sophisticated and extensive system of ancient Indian Occultism, possibly developed from the traditional Dravidian inhabitants, and from which many Eastern and Western practices are derived. It may also have been developed by the Aryan Warrior Class in reaction to Brahmanical control. It is also proclaimed to be the "revealed teaching" for this (the Kali Yuga) Age. Three distinct types of Tantra exist: Hindu Tantra, Buddhist Tantra, and Jain Tantra. Hindu Tantra also subdivides into North Indian and South Indian.

Tantra has become most identified with:

1) the Chakra system,
2) Kundalini, and
3) Sexual practices involving
    a) extended intercourse,
    b) complex positions and practices once considered "deviant," such as anal intercourse, oral intercourse, and the
        consumption of an ‘elixir’ compounded of the masculine and feminine fluids sucked from the vagina after
        intercourse and shared by the two lovers, and 
4) Worship of the partners, particularly the female, as the embodiment of Goddess and God.

Other occult principles and practices taken from Tantra include:

1) The Tattvas (the five basic elements and the twenty-five compounds visualized in meditation for psychic effects),
2) Yantras (complex geometric diagrams of energy circuitry visualized in meditation for psychic effects),
3) Mantras (chanting of sacred words and names in meditation for psychic effects),
4) Yoga Nidra (visualizations of psychic energy movements within the body during meditation), and
5) Other esoteric practices.

Suggested Reading:

Mumford: A Chakra & Kundalini Workbook: Psycho-Spiritual Techniques for Health, Rejuvenation, Psychic Powers & Spiritual Realization

Mumford: Yoga Nidra Meditation: Chakra Theory & Visualization (audio CD with instruction booklet)