Definition of "thorax" []

• The part of the human body between the neck and the diaphragm, partially encased by the ribs and containing the heart and lungs; the chest. (noun)
• A part in other vertebrates that corresponds to the human thorax. (noun)
• The second or middle region of the body of an arthropod, between the head and the abdomen, in insects bearing the true legs and wings. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "The entire hemi-thorax is treated with radiation therapy, often given simultaneously with chemotherapy."
• "It's thorax is short and thick, with long legs which protrude from it, initially, close together, then flair-out after the first joint."
• "Resembles vigilans, Nob., but the thorax is shorter and the lateral curvature is more regular, that of the preceding species being almost rectilinear from near the middle to the posterior angles; the colours also are different in their arrangement."