1. The shell of a clam
   "Children used clamshells to scoop sand at the beach"
    
2. A dredging bucket with hinges like the shell of a clam
   "The construction crew used a clamshell to excavate mud from the river bottom";
   - grapple

Derived forms: clamshells

Type of: dredging bucket, shell

Encyclopedia: Clamshell