‖n. [ NL., fr. Gr. &unr_; thorax + &unr_; pricking, from &unr_; to prick, stab. ] (Surg.) The operation of puncturing the chest wall so as to let out liquids contained in the cavity of the chest. [ 1913 Webster ]

n. [ Cf. F. thoracique. ] (Zool.) One of a group of fishes having the ventral fins placed beneath the thorax or beneath the pectorial fins. [ 1913 Webster ]

a. [ Cf. F. thoracique. ] (Anat.) Of or pertaining to the thorax, or chest. [ 1913 Webster ]

Thoracic duct (Anat.), the great trunk of the lymphatic vessels, situated on the ventral side of the vertebral column in the thorax and abdomen. See Illust. of Lacteal. [ 1913 Webster ]

‖n. pl. [ NL. ] (Zool.) A division of cirripeds including those which have six thoracic segments, usually bearing six pairs of cirri. The common barnacles are examples. [ 1913 Webster ]

n. (Physiol.) Same as Stethometer. [ 1913 Webster ]

n. [ Thorax + plasty. ] (Med.) A remodeling or reshaping of the thorax; especially, the operation of removing the ribs, so as to obliterate the pleural cavity in cases of empyema. [ 1913 Webster ]

‖n. pl. [ NL. See Thorax, and Ostracoid, a. ] (Zool.) An extensive division of Crustacea, having a dorsal shield or carapec&unr_; &unr_;&unr_;niting all, or nearly all, of the thoracic somites to the head. It includes the crabs, lobsters, shrimps, and similar species. [ 1913 Webster ]

n. [ Gr. &unr_;, &unr_;, thorax + &unr_; to cut. ] (Surg.) The operation of opening the pleural cavity by incision. [ 1913 Webster ]

a. [ L. torus a couch, bed. ] Of or pertaining to a bed. [ R. ] [ 1913 Webster ]

n. [ L., fr. Gr. &unr_;. ] 1. (Anat.) The part of the trunk between the neck and the abdomen, containing that part of the body cavity the walls of which are supported by the dorsal vertebrae, the ribs, and the sternum, and which the heart and lungs are situated; the chest. [ 1913 Webster ]

☞ In mammals the thoracic cavity is completely separated from the abdominal by the diaphragm, but in birds and many reptiles the separation is incomplete, while in other reptiles, and in amphibians and fishes, there is no marked separation and no true thorax. [ 1913 Webster ]

2. (Zool.) (a) The middle region of the body of an insect, or that region which bears the legs and wings. It is composed of three united somites, each of which is composed of several distinct parts. See Illust. in Appendix. and Illust. of Coleoptera. (b) The second, or middle, region of the body of a crustacean, arachnid, or other articulate animal. In the case of decapod Crustacea, some writers include under the term thorax only the three segments bearing the maxillipeds; others include also the five segments bearing the legs. See Illust. in Appendix. [ 1913 Webster ]

3. (Antiq.) A breastplate, cuirass, or corselet; especially, the breastplate worn by the ancient Greeks. [ 1913 Webster ]