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late 14c., from Latin ieiunum, neuter of ieiunus (see jejune). Translating Greek nestis (Galen). So called because it typically is found empty during dissections, perhaps because it would tend to drain in a body laid on its back.
jejunum je·ju·num (jə-jōō'nəm)
n. pl je·ju·na (-nə)
The section of the small intestine between the duodenum and the ileum.