Om, like many Sanskrit words, has been made confusing by the sheer number of interpretations. It has been described as the primeval sound, “all this,” God, Brahman, and a composite of three separate sounds symbolizing just about anything scripture describes in three’s: the three states of time (past, present, future), the three states of existence (waking, dreaming, deep sleep), the three bodies (gross, subtle and causal), the three aspects of the subtle body (mind, intellect and ego), the three powers (sattva, rajas and tamas), and the three synonyms for Brahman (sat-chit-ananda).
When one sees the symbol om or chants the mantra “om,” its significance should immediately and easily come to mind. For this reason, we might define om as simply “the force behind all creation.” By defining it this way, the sound-symbol becomes an abbreviated form of devotion, and a simple recognition of the great order that we are both in and a part of.
Om is that which enlivens the body, circulates your blood, digests your food, and grows the hair on your head. Om is the force and consciousness behind all beings including animals, plants and microorganisms. Om is that which governs the universal order, as well as creates, sustains and resolves it. It’s for this reason that many prayers, mantras and chants begin with om. To fully understand om, then, is the main objective of the truth seeker.
If we delve into the details regarding om, as defined by Vedanta, we find that it is utilized in two ways: (1) as a way to invoke the Lord—that which sustains and protects the Total in the form of order and (2) as a meditation in the third stage of Self-inquiry (nididhyasana) after one has gained Self-knowledge.
Symbolically, Vedanta describes om as the “four quarters,” which is the way it is depicted in the Mandukya Upanishad. The four quarters consist of the three states of experience: waking, dreaming and deep sleep, plus a fourth non-state which encapsulates the other three quarters: pure consciousness. Thus, om represents the complete human experience, both as form (empirical reality) and as the formless Self (absolute reality).
Om, as a mantra, is symbolically taught as three sounds—a-u-m. In Sanskrit, “au” is pronounced “o.” Thus, even though one describes the mantra as being an aggregate of the three syllables, a-u-m, it’s pronounced “om,” not “aum.” What do the three syllables represent? The same three states of experience: waking (a), dreaming (u) and deep sleep (m).
Swami Dayananda further defines “a” as the experience of the physical world, as well as the experience of the experiencer. “U” is the thought-world experienced while dreaming or fantasizing during waking hours. Lastly, “m” is the experience of deep sleep or “the unmanifest condition of world experience.” However, there’s an important fourth component and that is the silence that follows om, representing the all-encapsulating, never-changing, always present, Self. It’s for this reason that to fully understand and meditate on the significance of om, you need Self-knowledge, first.
In regards to practicing the mantra, Arsha Vidya UK recommends that “The 'o' in the word om should be pronounced by forming the lips into a tiny circle and making the vowel sound in 'go' or 'toe'. The vowel 'o' should be one long (dirgha) measure of sound. The labial sound 'm' should be short (hrasva) giving a total of three short measures for the duration of om.” Thus, one should chant it “o-o-m” and then focus one’s attention on the silence afterward before repeating the mantra again.