What does Aum or Om Symbol mean?

Aum or Om Symbol meaning in Symbols Dictionary

Aum or Om (in Devanagari ॐ) is one of the most sacred symbols in Hinduism. In Sanskrit known as praṇava (प्रणव) lit. "to seem down loudly" or oṃkāra (ओंकार) lit. "oṃ syllable")