Om Namah Shivaya is also called Panchakshara, the “five-syllable” mantra.Basically its meaning is adoration to shiva who is present in everywhere……..
There are many other meanings and interpretations to this maha mantra .The most beautiful one may be
Na signifies not or negation. mah means mine. So Namah means not mine. What is not mine? that belongs to Shiva
Thus this mantra, in its subtle meaning, emphasises negating our ego of possession and moving to the state of being possessed by the supreme being.
Another interpretation is that the 5 letters, represent the 5 primary elements which constitute the entire universe
Na is the sound of earth
Ma effects water factor
Shi energises the fire factor
Va energises the air factor
Ya energises the space
Everything in the universe, including our body is made up of these five basic elements. . So the mantra purifies the whole body and the surrounding.