Aum (also Om, written in Devanagari as ॐ, in Chinese as 唵, in Tibetan as ༀ, in Sanskrit known as praṇava प्रणव lit. "to sound out loudly" or oṃkāra ओंकार lit. "oṃ syllable") is a mystical or sacred syllable in the Indian religions, including Hinduism, Sikhism, Jainism, and Buddhism. http://en.wikipedia.org/wiki/Om