Aum , the universal name of the Lord is made up of three letters A U and M. The sound emerges from the base of the throat as A. When the lips come together U is formed. When the lips are closed, the sound ends in M. Besides the three states of onsciousness, the three letters are supposed to signify various fundamental triads such as
The three deities – Brahma, Vishnu, Shiva
The three vedas – Rig, yajur, sama
The three gunas – satva, rajas, thamas
The three worlds – Bhuh, Bhuvah, Suvah

The silence between the chanting of two Aums represent the Lord who has no attributes.

This Aum chanting fills the mind with peace and focusses it and is the symbol of cosmic reality. While meditating, when we chant Aum, we create within ourselves a vibration that attunes sympathy with the cosmic vibration and we start thinking universally.

Thus Aum, the supreme and most sacred syllable is the spoken essence of the universe. It is uttered as a mantra and in affirmations and blessings. In a nutshell Aum symbolises everything – the means and the goal of life, the world and the Truth behind it, the material and the Sacred, all forms and the formless.