Aum is the paramount sound, origin of creation, the seed from which the language is resulting. All the sounds which exist come from its Aum. This sound means “I accept”. Aum or Om is the highest symbol of Hindu knowledge. “The presence of the Absolute in the world”. Used the beginning of each rite, it makes it possible to reach the divine one. To the three letters the three tendencies of Trimurti correspond: - “With”: It is Brahmâ, the waking state, the origin of creation, the terrestrial world. - “U” represents Vishnu, the cohesive tendency, the intermediate world. “U” is the state of dream since it is in its sleep that Vishnu prepares the next life cycle. - “M” is Shiva the centrifugal force, that which destroys all. “M” is the state of deep sleep, the celestial world. One adds to it a half letter (ardha-mâtrâ) that only the yogis can perceive. It represents the lunar world, out of reach of the thought and the word. Mandukya Upanishad analyzes the significance of Aum. The syllable is described as the arc which launches the arrow of self (the atman) towards the target of the absolute (the brahman). It is “the syllable single and eternal of which all that exists is a development; the past, the present, the future all are included in this single sound”. De Aum results all the verbal seeds (will bija-mantra).