What is the significance of the sacred word 'A.U.M.' in Freemasonry?

Mackey treats Aum (or Om) as a triliteral sacred syllable signifying the Supreme God, in which the letters A, U, and M represent the Creator, Preserver, and Destroyer (Brahma, Vishnu, and Siva) 1. The three letters are credited with mysterious power and sanctity, representing the spiritual Sun or Source of Inner Light 1.

In comparative discussions of sacred terms in the Royal Arch, Aum is analyzed alongside other mystical names 1. Mackey holds that Aum cannot be equated or interchanged with the word On, because the letter 'm' in Aum serves as the initial of a secret word and would lose its proper Masonic signification if altered 1.