Interviewer: Master Chinmoy, I am curious about the meaning of these three letters which you pronounce “AUM.”

Sri Chinmoy: AUM is a Sanskrit syllable, or you can say, a complete word. We have, in India, the Trinity: Brahma, Vishnu and Siva — the Creator, Preserver and Transformer. A represents Brahma the Creator, U represents Vishnu the Preserver and M represents Siva the Transformer. And this AUM is the breath of the Supreme. The Indian sages, seers and yogins of yore chanted this AUM and they got their souls' illumination and liberation. Even now, most of the seekers in India chant AUM most devotedly. They will have their Realisation by chanting AUM, the Power Infinite.

From: Sri Chinmoy, AUM — Vol. 3, No. 3,4, Oct. — Nov. 27, 1967 - , Boro Park Printers -- Brooklyn, N. Y., 1967
Sourced from http://www.srichinmoylibrary.com/aum-254