‖Il″e‐um (?), n. [L. ile, ileum, ilium, pl. ilia, groin, flank.] 1. (Anat.) The last, and usually the longest, division of the small intestine; the part between the jejunum and large intestine. [Written also ileon, and ilium.]
2. (Anat.) See Ilium.
☞ Most modern writers restrict ileum to the division of the intestine and ilium to the pelvic bone.