bivalve vs clamshell

bivalve

noun
  • Any mollusc belonging to the taxonomic class Bivalvia, characterized by a shell consisting of two hinged sections, such as a scallop, clam, mussel or oyster. 

  • A pericarp in which the seed case opens or splits into two parts or valves. 

clamshell

noun
  • Any object with some other resemblance to either one or both halves of the shell of a clam. 

  • In food service, the closing box (usually styrofoam but sometimes cardboard) given to consumers with take-out food. 

  • The shell of a clam. 

  • Any object that, in (literal or figurative) resemblance to the shell of a clam, has a hinge on one edge and two surfaces that close together. 

  • A dredging bucket with hinges like the shell of a clam. 

  • An amphitheater, especially an outdoor amphitheater; the semi-circular acoustic backdrop behind and above the performers. 

verb
  • To dig out by means of a clamshell (dredging bucket). 

  • To compress or flatten underwater debris so as to avoid blocking a channel. 

  • To open or close by means of a hinge, similar to the way a clamshell opens and closes. 

  • To deform a die in a shape resembling the shell of a clam, as a result of uneven extrusion pressure. 

How often have the words bivalve and clamshell occurred in a corpus of books? (source: Google Ngram Viewer )