Its expression is the Praṇava [Om].

Praṇava is the technical name for the sacred sound Om (ॐ). Vācaka means “that which expresses” or “designator.” Om is not an arbitrary symbol for Īśvara but its natural sonic expression.

In Indian tradition, there exists an intrinsic relationship between the name and the named. Om contains in sound form the essence of Īśvara. This is why its repetition has transformative power.

Om is considered the primordial sound of the universe, present in all Vedic traditions. It is simultaneously the most concentrated and most universal symbol of the divine, accessible to practitioners of any tradition.