Om is the most sacred syllable often spoken during the practice of any Hindu rites. It is a holy character of the Sanskrit language, the language of God. The character is a composite of three different letters of the Sanskrit alphabet. The English equivalent of those are "a", "u", and "m", and represent the Trinity. The Trinity is composed of the three supreme Gods: Brahma, the creator, Vishnu, the preserver, and Shiva, the destroyer. These three letters when pronounced properly in unison create an invigorating effect in the body. Because of its significance this sacred syllable is spoken before any chants to show God we remember him. This sign also represents the whole universe.
What is the Meaning of Aum or Om?