jejunum

Concise Oxford English Dictionary © 2008 Oxford University Press:
jejunum /dʒɪˈdʒuːnəm/

▶noun Anatomy the part of the small intestine between the duodenum and ileum.

– derivatives
jejunal adjective.

– origin C16: from med. L., neut. of jejunus ‘fasting’ (because it is usu. found to be empty after death).