OM [ Also spelled Aum ] is a Hindu sacred sound that is considered the greatest of all mantras. The syllable Om is composed of the three sounds a-u-m [ in Sanskrit, the vowels a and u combine to become o. It is the sound of life. Emitting the aaauuummm sound mimics the harmonic tone of all creation. Thus OM mystically embodies the essence of the entire universe. This meaning is further deepened by the Indian philosophical belief that God first, created sound and the universe arose from it. As the most sacred sound, OM is the root of the universe and everything that exists and it continues to hold everything together.