Om (or Auṃ [ə̃ũ], Sanskrit: ॐ) is a sacred sound and a spiritual icon in Dharmic religions.[1] It is also a mantra in Hinduism,Buddhism and Jainism.[2][3] In Hinduism, Om is a spiritual symbol (pratima)[4] referring to Atman (soul, self within) and Brahman(ultimate reality, entirety of the universe, truth, divine, supreme spirit, cosmic principles, knowledge).[5][6][7]
The syllable is one of the most important symbols in Hinduism,[8] and is often found at the beginning and the end of chapters in theVedas, the Upanishads, and other Hindu texts.[7] (source)