n, pl  -de*na  or  -de*nums  :  the first, shortest, and widest part of the small intestine that in humans is about 10 inches (25 centimeters) long and that extends from the pylorus to the undersurface of the liver where it descends for a variable distance and receives the bile and pancreatic ducts and then bends to the left and finally upward to join the jejunum near the second lumbar vertebra du*o*de*nal adj 
 
   
 
Similar sounding terms:  ti·ta·ni·um 
 
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