The word shankha means ‘shell’ or ‘conch’, the type that one can so easily find on a quiet beach. Therefore, the English translation of this mudra is ‘conch mudra’.
The conch is an integral part of religion, for many of the deities, such as Vishnu, Lakshmi and Shiva are shown blowing or holding this symbolic object. Even in the opening chapter of the Bhagavad Gita Krishna and Arjuna blow their conches: “Then, Madhava (Krishna) and the son of Pandu (Arjuna) who were seated in their magnificent chariot, yoked with fine white horses, blew their divine conches.” (1:14)
In ancient European tradition also, the conch is often utilized. For example, the tritons used the conch as a trumpet.
The most obvious thing that this conch, or rather its sound represents, is the cosmic, inner sound of each and every individual. This is the sound that links the individual with highest consciousness, like a puppet on a string. This is called nada, or shabda, in Sanskrit. This is logos in some of the western traditions. When the conch is blown it makes a penetrating sound like a long Aum. This is the reason it is sounded during religious ceremonies.
While sitting for meditational practice the most comfortable method of holding this mudra is to position the hands as shown, then rest them on your lap.