You may have wondered what ‘OM’ is all about;
Om (IAST: Auṃ or Oṃ, Sanskrit: ॐ) is a sacred sound and a spiritual icon in Indian religions. It is also a mantra in Hinduism, Buddhism and Jainism.
Om is part of the iconography found in ancient and medieval era manuscripts, temples, monasteries and spiritual retreats in Hinduism, Buddhism, and Jainism. The symbol has a spiritual meaning in all Indian dharmas, but the meaning and connotations of Om vary between the diverse schools within and across the various traditions.
In Hinduism, Om is one of the most important spiritual symbols (pratima). It refers to Atman (soul, self within) and Brahman (ultimate reality, entirety of the universe, truth, divine, supreme spirit, cosmic principles, knowledge) – read more here – https://en.wikipedia.org/wiki/Om