Om (Aum)
Also known as: Aum, Pranava
Sanskrit: Om or Aum; described in the Mandukya Upanishad as the sound-symbol of ultimate reality.
Om, often written Aum, is considered in Indian traditions to be the primordial sound underlying all creation and is chanted at the start and end of yoga and meditation practices. Its three phonetic parts, A, U, and M, are traditionally said to correspond to waking, dreaming, and deep sleep, with the silence after representing Turiya.
The Mandukya Upanishad devotes its entirety to explaining Om as representing all of reality across the four states of consciousness. Modern research on OM chanting has measured its effects on the autonomic nervous system and on auditory evoked potentials, generally finding shifts consistent with a relaxation response, though these findings describe physiological correlates rather than validating the traditional metaphysical claims about the syllable.
The Mandukya Upanishad, one of the shortest but most philosophically dense Upanishads, is devoted entirely to unpacking Om's three sounds, A, U and M, as waking, dreaming and deep sleep, with a fourth, silent state, turiya, represented by the sound's natural fading into stillness. It is chanted at the start and close of many yoga and meditation sessions across traditions; while exact pronunciation and symbolic elaboration vary by lineage, the sound predates any single school and appears throughout the Vedic corpus as a foundational syllable.
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Related Terms
Mantra
A mantra is a word, sound, or phrase repeated silently or aloud during meditation or ritual, used to focus the mind, invoke a particular quality, or mark a state of consciousness. Mantras range from a single syllable, such as Om, to longer Sanskrit phrases associated with specific deities or intentions.
Turiya
Turiya is the 'fourth state' of consciousness described in the Mandukya Upanishad, distinct from waking, dreaming, and dreamless sleep. It refers to pure awareness itself, the constant background presence in which the other three states arise and pass.