Om is not a word, rather it is an intonation; a deep sound, which, like music, transcends the barriers of age, race, culture and even species. It is made up of three Sanskrit letters: aa, au and ma which, when combined together, make the sound Aum or Om.The mantra “OM” is the name of God, the vibration of the Supreme. It is believed to be the basic sound of the world and is a mantra or prayer in itself.
The Gospel of Sri Ramakrishna says that the rishis and sages practiced austerity to realize this Sound. After attaining perfection one would hear the sound of this eternal Word rising spontaneously from the navel. “‘What will you gain’, some sages ask, ‘by merely hearing this sound?’.You hear the roar of the ocean from a distance. By following the roar you can reach the ocean. As long as there is the roar, there must also be the ocean. By following the trail of OM you attain the Supreme, of which OM is the symbol and that has been described by the Vedas as the ultimate goal”.
If repeated with the correct intonation, it can resonate throughout the body so that the sound penetrates to the centre of one’s being, the atman or soul. However the holy texts emphasize, “The repetition of OM should be made with an understanding of its meaning”.