Shankha is said to be derived from the rakshasa Shankha-asura.
It is the symbolism of Tat-Sat and is blown thrice before Puja. It is kept as a dharmic symbol. It symbolizes vijay at a deeper level. Blowing the Shankha (Conch) emanates Pranava (AUM). The whole vedic knowledge is contained in the Pranava.
Shankha-Asura vanquished the Devas and stole the Vedas from them. *Note the word Devas rearranged as Vedas. He is supposed to have taken the Vedas and gone to the the bottom of Sagara (Ocean of consciousness). The devas turned to Naarayana for help. Naraayana took the avatara of Matsya (Meena, Fish) and vanquished the Asura. Lord Vishnu then blew the Shankha which hung from his ears and AUM vibrated thru which the Vedas came back. The 2nd Bhava for this reason only is connected to knowledge of the Vedas or AUM (Pranava). A spiritual connector to 2nd Bhava shows the evoluted soul with knowledge of the Vedas.
And there are related connections between Shankha and Shankara.
OM Tat Sat