Otherwise called “Pranavam”, is a Symbol rather than a word. And also it is a very lot, more than a symbol as per the scriptures of “Sanathana Dharma”.
“Ohmiteyditi A^ksharamidam° ¶ Sarvam°¶” –
Of all the effable and ineffable sounds, Ohm is the First sound. Also called “Anaahatha”(the unstruck sound ) .