OM (AUM)

"AUM" is a word that represents to our ears that sound of the energy of the universe of which all things are manifestations. You start in the back of the mouth "ahh," and then "oo," you fill the mouth, and "mm" closes the mouth. When you pronounce this properly, all vowel sounds are included in the pronunciation. AUM. Consonants are here regarded simply as interruptions of the essential vowel sound. All words are thus fragments of AUM, just as all images are fragments of the Form of forms. AUM is a symbolic sound that puts you in touch with that resounding being that is the universe. If you heard some of the recordings of the Tibetan monks chanting AUM, you would know what the word means, all right. That's the AUM of being in the world. To be in touch with that and to get the sense of that is the peak experience of all.

A-U-M. The birth, the coming into being, and the dissolution that cycles back. AUM is called the "four-element-syllable." A-U-M - and what is the fourth element? The silence out of which AUM arises, and back into which it goes, and which underlies it. My life is the A-U-M, but there is a silence underlying it, too. That is what we would call the immortal. This is the mortal and that's the immortal, and there wouldn't be the mortal is there weren't the immortal. One must discriminate between the mortal aspect and the immortal aspect of one's own existence. In the experience of my mother and father who are gone, of whom I was born, I have come to understand that there is more than what was our temporal relationship. Of course there were certain moments in that relationship when an emphatic demonstration of what the relationship was would be brought to my realization. I clearly remember some of those. They stand out as moments of epiphany, of revelation, of the radiance.

Article: OM: An Inquiry into its Aesthetics, Mysticism, and Philosophy