In short
Om, also written AUM, is the most important sacred sound in the Indian traditions. The Upanishads treat it as a symbol of the whole of reality, and the Yoga Sutras call it the word that expresses the divine. Its three sounds, A, U and M, are traditionally linked to waking, dreaming and deep sleep, and the silence after it to a fourth state beyond all three. Chanted at the start and end of practice, it gathers attention and marks the time as different.
Om — written ॐ in Devanagari — is almost certainly the most familiar sound in all of yoga. It is on tattoos, mats and shop signs. What it actually means is less familiar, and more interesting.
A sound, not a word
Om is not a word with a dictionary meaning the way "peace" or "breath" is. In the Indian traditions it is treated as a sound-symbol: the audible form of something that cannot otherwise be put into words. It is sometimes called pranava, which is often interpreted as "the humming one" or "that which is ever new"; the derivation is debated.
It appears across Hinduism, Buddhism, Jainism and Sikhism, usually at the start and end of prayers, recitations and practices. Many Sanskrit mantras begin with it.
Why it is written AUM
In Sanskrit, the vowels a and u combine into a sound close to o. So Om is, phonetically, three sounds: A, U and M. When it is chanted slowly you can hear them separate, and that separation is where most of the traditional teaching about it comes from.
What the texts say
The Mandukya Upanishad, one of the shortest and most studied of the Upanishads, is devoted entirely to Om. It links each part of the sound to a state of consciousness:
- A — the waking state, experience of the outer world.
- U — the dreaming state, experience of the inner world.
- M — deep, dreamless sleep.
- The silence after — turiya, "the fourth": pure awareness underlying all three.
That last point matters. In this reading, the silence is as much a part of Om as the sound. It sits at the heart of Vedanta, the philosophy the school takes its name from.
Patanjali's Yoga Sutras are briefer. They say the divine is expressed by the pranava, and that repeating it while reflecting on its meaning removes obstacles and turns the mind inward. That is the root of Om as a meditation practice, and there is more in the Yoga Sutras explained.
Why classes use it
At the start of a class, Om works as a threshold. A room of people who arrived separately, from different streets and different moods, make one sound together and the room changes. Attention collects. The practice has begun.
At the end, it works the other way: it gathers up what the practice produced before everyone walks back out. It is often followed by "shanti, shanti, shanti", the threefold wish for peace that gives the school its name.
There is also a plainly physical effect. A long, low hum lengthens the exhale and vibrates through the chest and head, and many people find that settling in itself.
How to chant it
- Sit tall and take a full breath in.
- Begin with an open "ah", felt low in the belly.
- Let it round into "oo", felt in the chest.
- Close the lips into "mmm", felt humming in the head.
- Let the sound end and sit in the silence for a few breaths.
The "mmm" is usually the longest part. Do not strain for volume; a soft, steady tone is better than a loud one. In a group, you do not need to match anyone's pitch — just join in.
Chanting Om three times, slowly, then sitting quietly for a minute is itself a complete short practice, and a gentle way into daily meditation.
Do you need to believe anything?
No. Plenty of people chant Om for the effect on the breath and attention and leave the metaphysics alone. Others find the meaning deepens with years of practice. Both are fine, and no teacher worth practising with will ask you which one you are.
If chanting makes you self-conscious, listen instead for the first few classes. Nobody will mind, and most people find that after a week or two they have joined in without noticing.
Common questions
What does Om mean?
Om is a sacred sound-symbol in the Indian traditions rather than a word with a dictionary meaning. The Upanishads treat it as the audible form of the whole of reality, and the Yoga Sutras as the sound that expresses the divine.
Why is Om written AUM?
In Sanskrit, the vowels a and u combine into a sound close to o, so Om is three sounds: A, U and M. The Mandukya Upanishad links them to waking, dreaming and deep sleep, and the silence after to a fourth state beyond all three.
Why do yoga classes start and end with Om?
At the start it gathers attention and marks the practice as having begun; at the end it gathers what the practice produced. The long hum also lengthens the exhale, which is settling in itself.
Do I have to chant Om in a yoga class?
No. Chanting is always optional. Many people listen for the first few classes and join in when they feel ready.
Known to his students as Achu, Aksharanand trained in the Sivananda tradition and holds an Advanced Teacher Training Certificate. He has taught Hatha Yoga, pranayama, meditation and Vedanta philosophy in Fort Kochi for over fifteen years, across more than 5,000 group classes and seventy international teacher training batches.
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