mussel vs oyster

mussel

noun
  • A freshwater mussel, usually edible, of the order Unionida in subclass Palaeoheterodonta. 

  • A saltwater mussel, usually edible, of the order Mytilida in subclass Pteriomorphia. 

  • Any of certain other bivalves of somewhat similar appearance, such as the zebra mussel and quagga mussel of the family Dreissenidae in subclass Heterodonta. 

oyster

noun
  • Any of certain marine bivalve mollusks, especially those of the family Ostreidae (the true oysters), usually found adhering to rocks or other fixed objects in shallow water along the seacoasts, or in brackish water in the mouth of rivers. 

  • A person who keeps secrets. 

  • A shoplifter. 

  • A pale beige color tinted with grey or pink, like that of an oyster. 

  • The delicate morsel of dark meat contained in a small cavity of the bone on each side of the lower part of the back of a fowl. 

verb
  • To fish for oysters. 

adj
  • Of a pale beige colour tinted with grey or pink, like that of an oyster. 

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