ileum n 1: the part of the small intestine between the jejunum and the cecum
Ileum \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}.] [1913 Webster] 2. (Anat.) See {Ilium}. [R.] [1913 Webster] Note: Most modern writers restrict ileum to the division of the intestine and ilium to the pelvic bone. [1913 Webster]
Ilium \Il"i*um\, n. [See {Ileum}.] (Anat.) The dorsal one of the three principal bones comprising either lateral half of the pelvis; the dorsal or upper part of the hip bone. See {Innominate bone}, under {Innominate}. [Written also {ilion}, and {ileum}.] [1913 Webster]