n, pl  tho*rax*es  or  tho*ra*ces   1  :  the part of the mammalian body that is situated between the neck and the abdomen and supported by the ribs, costal cartilages, and sternum : also  :  THORACIC CAVITY  2  :  the middle of the three chief divisions of the body of an insect : also  :  the corresponding part of a crustacean or an arachnid .
 
   
 
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