ileum

n. third and lowest section of the small intestine (Anatomy)

In anatomy of the digestive system, the ileum is the final section of the small intestine. It is about 2-4 m long in humans, follows the duodenum and jejunum, and is separated from the cecum by the ileocecal valve (ICV). The pH in the ileum is usually between 7 and 8 (neutral or slightly alkaline).
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Ileum /il·e·um/ the distal portion of the small intestine, extending from the jejunum to the cecum. [more]Ileum - Community and Resources

Noun
1. the part of the small intestine between the jejunum and the cecum
(hypernym) small intestine

(n.)
The last, and usually the longest, division of the small intestine; the part between the jejunum and large intestine.
  

(n.)
See Ilium.