Vam is the seed syllable (bija mantra) of svadhisthana, the sacral chakra placed below the navel, in the tantric and hatha-yoga chakra system. Each principal centre in this scheme is meditated upon through a governing element, a lotus of a set number of petals, and a seed sound; svadhisthana is associated with the element water and with a six-petalled lotus, and Vam is the sound used to concentrate upon and, in the tradition's understanding, to awaken it. As with the other bijas, Vam is not a word to be translated but a sound treated as the sonic essence of the centre and its watery element, used in inward recitation and visualisation as the practitioner works up the subtle body from the root toward the crown. The assignment derives from the medieval tantric sources later codified in the yoga literature, and it is standard across the common forms of the system.
Vam is identified in the tantric physiological scheme known from Purnananda Yati's sixteenth-century Sanskrit text the Shatchakra Nirupana, translated and extensively annotated in English by Sir John Woodroffe, writing under the pen name Arthur Avalon, in The Serpent Power (1919), as the bija, or seed syllable, of the Svadhisthana chakra, the sacral centre, traditionally visualised as a six-petalled lotus at the base of the spine above the root centre. In this scheme each of the body's principal energy centres is assigned its own single-syllable seed sound, and Vam's recitation, typically as part of a structured kundalini or chakra meditation practice, is held within that tradition to activate or attune the practitioner's awareness to the qualities, water, fluidity and the emotional and creative faculties, traditionally associated with this particular centre.