....what you always wanted to know about OOOMMMM....

OM

The mantra Om is composed of three letters, viz. A… U… and  M  .

Of these the first two vowels coalesce to form  O  . Over the O  is written the sign of candra (moon like shape) which is the nada and bindu (dot). Nada and bindu are the two aspects of the Mother or Great Power (Maha Sakti)- She is both efficient and the material cause of the universe.  A  U and M represent the trinity of will (iccha), knowledge (jnana) and action (karma) in the form of Brahma, Visnu and Rudra.

Bhagwan Dash, Lalitesh Kashyap, Basic Principles of Ayurveda