Om or Aum is a sacred sound and a spiritual symbol in Indian religions. It signifies the essence of the ultimate reality, consciousness or Atman. More broadly, it is a syllable that is chanted either independently or before a spiritual recitation.
In Hinduism, Om is one of the most important spiritual symbols. It refers to Atman (soul, self within) and Brahman (ultimate reality, entirety of the universe, truth, divine, supreme spirit, cosmic principles, knowledge).
It’s a sacred syllable that is considered to be the greatest of all the mantras, or sacred formulas. The syllable om is composed of the three sounds a-u-m (in Sanskrit, the vowels a and u coalesce to become o). Thus, om mystically embodies the essence of the entire universe. It is uttered at the beginning and end of Hindu prayers, chants, and meditation and is also freely used in Buddhist and Jain ritual. From the 6th century, the written symbol designating the sound has been used to mark the beginning of a text in a manuscript or an inscription.
Om is like the Zamboni for the mind. It’s a mental reset with scientific backing. A study published in the International Journal of Yoga found that chanting Om reduced activity in the limbic system, the part of the brain associated with stress and emotions. Studies show that silent repetition does have an effect. The power of Om is greater than the aural sound.

There are three different sounds of Om (A-U-M) .
The bottom left curve represents the sound of A (aahh) and the first or waking state of consciousness. This is our conscious mind and where we experience the world through the five senses. The bottom right curve represents the sound of U (oohh) and the second or dreaming state of consciousness. We experience this beyond our physical bodies in our active unconsciousness and energetic realms. The top left curve represents the sound of M (mmm) and the third or deep sleeping state of consciousness. Represents the spiritual forces of the universe and the connectivity it provides. The dot located at the top represents the silence after chanting Aum and the fourth or samadhi state of pure consciousness. This is the highest state of consciousness where you experience absolute stillness and oneness with all creation.
Om is a very simple sound with a complex meaning. It is the whole universe coalesced into a single word, representing the union of mind, body, and spirit that is at the heart of yoga.
The sound of om is said to contain the entire universe. It is the first sound from the beginning of time, and it also encompasses the present and the future. As such, its importance and power are difficult to overstate. In a yoga setting, the chanting of om at the beginning of class ushers practitioners into the time and space that is about to be spent on the mat or in meditation. Likewise, an om at the end of class signifies that your physical practice has ended and it is time to re-enter society.
Chanting with a group of people also serves to unify the group and create a sense of community. As you feel the vibration of the chant and lose the sound of your own voice among those of your classmates, it’s possible to feel at one with other people and even with the universe.
The sound Om, when chanted, vibrates at the frequency of 432 Hz, which is the same vibrational frequency found throughout everything in nature. As such, AUM is the basic sound of the universe, so by chanting it, we are symbolically and physically acknowledging our connection to nature and all other living beings.