(Sanskrit त्रिवेणी) A feminine word. Literally, "Triple-braided, the place where three holy rivers meet, place of confluence of the rivers Ganges, Yamuna, and subterranean Sarasvati."
"The Nadis of each side Ida and Pingala are the left and right sympathetic cords crossing the central column from one side to the other, making at the Ajna with the Sushumna a threefold knot called Triveni; which is said to be the spot in the Medulla where the sympathetic cords join together and whence they take their origin—these Nadis together with the two lobed Ajna and the Sushumna forming the figure of the Caduceus of the God Mercury which is said by some to represent them... Ida starts from the right testicle and Pingala from the left testicle. They meet with Sushumna Nadi at the Muladhara Chakra and make a knot there. This junction of three Nadis at the Muladhara Chakra is known as Mukta Triveni. Ganga, Yamuna and Sarasvati dwell in Pingala, Ida and Sushumna Nadis respectively. This meeting place is called Brahma Granthi. Again these meet at the Anahata and Ajna Chakra. In the macrocosm also you have a Triveni at Prayag where the three rivers Ganga, Yamuna and Sarasvati meet." - Swami Sivnanada, Kundalini Yoga
"There is a vast inexhaustible magazine of power and knowledge within. Learn the ways to tap the source. Dive deep within. Sink down. Plunge in the sacred waters of immortality-the holy Triveni (triple stream confluence where river Ganga and Yamuna meet along with the invisible underground river Saraswati)." - Swami Sivnanada, Practical Way to Self-realization
"It is said that there are 3½ crores of nadi in the human body, of which some are gross and some are subtle. Nadi means a nerve or artery in the ordinary sense; but all the nadis of which the books on Yoga speak are not of this physical character, but are subtle channels of energy. Of these nadi, the principal are fourteen; and of these fourteen, ida, pingala, and sushumna are the chief; and, again, of these three sushumna is the greatest, and to it all others are subordinate. Sushumna is in the hollow of the meru in the cerebro-spinal axis. It extends from the Muladhara lotus, the Tattvik earth centre, to the cerebral region. Sushumna is in the form of Fire (vahni-svarupa), and has within it the vajrini-nadi in the form of the sun (surya-svarupa). Within the latter is the pale nectar-dropping chitra or chitrini-nadi, which is also called Brahma-nadi, in the form of the moon (chandra-svarupa,). Sushumna is thus triguna. The various lotuses in the different Chakra of the body (vide post) are all suspended from the chitra-nadi, the chakra being described as knots in the nadi, which is as thin as the thousandth part of a hair. Outside the meru and on each side of sushumna are the nadi ida and pingala. Ida is on the left side, and, coiling round sushumna, has its exit in the left nostril. Pingala is on the right, and, similarly coiling, enters the right nostril. The sushumna, interlacing ida and pingala and the ajna-chakra round which they pass, thus forms a representation of the caduceus of Mercury. Ida is of a pale colour, is moon-like (chandra-svarupa), and contains nectar. Pingala is red, and is sun-like (suryya-svarupa), containing "venom," the fluid of mortality. These three "rivers," which are united at the ajna-chakra, flow separately from that point, and for this reason the ajna-chakra is called mukta triveni. The muladhara is called Yukta (united)-tri-veni, since it is the meeting-place of the three nadi, which are also called Ganga (Ida), Yamuna (Pingala), and Sarasvati (sushumna), after the three sacred rivers of India. The opening at the end of the sushumna in the muladhara is called brahma-dvara, which is closed by the coils of the sleeping Devi Kundalini." - Arthur Avalon