The Proto-Indo-European word *k̂on-
Word *k̂on-
Meaning shell

Comments
Lat. conguius, Gk. kogkhos, Skr. śaṅ kha

Other words that might be of interest
*dʰĝʰu- ‘fish’, *laks- ‘salmon’, *peisk ‘fish’, *dhĝhuhₓ- ‘fish’, *karkr(o)- ‘crab’, *pik̂sk̂os ‘fish, trout’