OM’-The symbol is comprised of three syllables put into one. In Sanskrit the vowel "o" is constitutionally a diphthong compound of a + u; hence OM is representatively written as AUM. The symbol of AUM is formed by three curves (curves 1, 2, and 3), one semicircle (curve 4), and a dot.
Symbolism behind the three Curves of OM:
Large Lower Curve:
The large lower curve forms the waking state (jagrat), in this state the consciousness of a human is turned towards the gate of sense. The larger size of the curve signifies state of human consciousness.
The Upper Curve:
The upper curve represents the state of deep slumber (sushupti) in other words, the unconscious state. This is a state where the human has no desire of anything nor does he have a dream.
The Middle Curve:
The middle curve implies the dream state (swapna). In this state the consciousness of a person is turned inwards, and the person who dreams holds an exciting view of the world.
The above-mentioned signs are the three states of a person's consciousness, and thus these three curves represent the whole physical phenomenon.
Symbolism behind the Dot:
The dot in the Aum signifies the fourth state of consciousness, which in Sanskrit is known as ‘turiya.’ This state signifies the coming to rest of all relative existence. This quiet and peaceful state is the ultimate goal of all Hindus.
Symbolism behind the Semi Circle:
Finally, the semi circle in the OM symbolizes "Maya" (illusion). This illusion or maya prevents us from the achievement of bliss. This effect is used to prevent the seeker from reaching his ultimate goal, the realization of the One, and all-pervading, absolute principle.
Symbolism behind the Sound of OM:
As regards the sound and form, AUM is symbolic of Brahma and the whole universe.
§ A symbolizes Creation
§ U symbolizes Preservation
§ M symbolizes Destruction
The three sounds also symbolize the three Vedas (Rig-Veda, Sam Veda, and Yajur Veda).
This is in other words represents the Trinity in Hindu Dharma namely Brahma, Vishnu and Shiva.
Other Symbolism behind OM:
§ The three letters in AUM also indicate three planes of existence, called heaven, earth and netherworld.
§ AUM can represent all the words produced by the human vocal organ. This can be said because; A is produced by the throat and U & M by the lips.
§ According to the Vedas, AUM is associated with the sound of the Sun and also the sound of Light.
§ It symbolizes the sound of the infinite.
But overall the nature of OM is threefold. It is a sacred sound. It forms the essence of all mantras. It is the ultimate reality (Brahma). It is also said to be the central essence of the Vedas.
While meditating, if we chant OM, we create within ourselves a vibration that connects us with the cosmic vibration and we start thinking universally. The silence between each chant becomes felt physically. The Mind moves from the opposites of sound and silence until the sound ceases. In this silence, there is no thought. This is the state of trance.