spelled ohm, om or aum, the sound ohm is from the ancient, sacred hindi language of sanskrit. while chanting ohm, one aligns themselves with their highest self, and seeks to achieve oneness and peace with the universe. ohm is chanted in meditation, and is the traditional mantra in both hinduism and buddhism. called the eternal ohm, it is believed to be the first sound ever made.
the tibetan ohm has the same meaning, but the symbol is slightly different.