/ Dictionary / Index I ileum: Meaning and Definition of Find definitions for: il•e•um Pronunciation: (il'ē-um), [key] — pl. il•e•a the third and lowest division of the small intestine, extending from the jejunum to the cecum. See diag. under the anterior portion of the hindgut of an insect or other arthropod. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ileum (Thesaurus) Iletin ileus Related Content Daily Word Quiz: spectral Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language