je·ju·num 
(jə-jnəm)
(jə-jnəm)n. pl. je·ju·na (-nə)
The section of the small intestine between the duodenum and the ileum.
[Middle English, from Medieval Latin iēiūnum (intestīnum), fasting (intestine) (so called because in dissection it was always found empty), neuter of Latin iēiūnus.]