[1] : The Collaborative International Dictionary of English v.0.48

jejunum \jeju"num\, n. nl., fr. l. jejunus empty, dry.
   anat.
   the middle division of the small intestine, between the
   duodenum and ileum; -- so called because usually found empty
   after death.
   1913 webster

[2] : WordNet (r) 2.0

jejunum
     n : the part of the small intestine between the duodenum and the
         ileum

Jejunum >> J Words
Jejunum, definition of term: Jejunum
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