Definition of file shell in English:

file shell

noun

  • A free-swimming bivalve mollusc, the shell of which is typically white and has a rough, ribbed external surface.

    • ‘The crab was presumably going to try to break it open as soon as possible, but the file shell's acid secretions may have permitted a last-minute escape.’
    • ‘A spiny file shell can use its foot to bounce up from the bottom and can swim, but file shells have no eyes.’
    • ‘The file shell, like the scallop, can move very rapidly by clapping its shells together.’