n.
   - a bivalve marine mollusc with a rough, flattened, irregularly oval shell, several kinds of which are farmed for food or pearls. 
[Ostrea edulis (Europe), Crassostrea virginica (America), and other species.]
 - a shade of greyish white.
 - an oval morsel of meat on each side of the backbone in poultry.
 
 
  Phrase
  
    
      - the world is one's oyster
 one is in a position to enjoy a broad range of opportunities. 
[from Shakespeare's Merry Wives of Windsor (ii. ii. 5).]
 
    
   
  Etymology
  ME: from OFr. oistre, via L. from Gk ostreon; rel. to osteon ‘bone’ and ostrakon ‘shell or tile’.