The Collaborative International Dictionary of English v.0.48:

Ileus \Il"e*us\, n. [NL., fr. Gr. ?, ?, fr. ? to roll up.]
   (Med.)
   A morbid condition due to intestinal obstruction. It is
   characterized by complete constipation, with griping pains in
   the abdomen, which is greatly distended, and in the later
   stages by vomiting of fecal matter. Called also ileac
   passion or iliac passion.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Iliac \Il"i*ac\, a. [Cf. F. iliaque. See Ileum, and cf. Jade
   a stone.]
   1. (Anat.) Pertaining to, or in the region of, the ilium, or
      dorsal bone of the pelvis; as, the iliac artery. [Written
      also ileac.]
      [1913 Webster]

   2. See Ileac, 1. [R.]
      [1913 Webster]

   Iliac crest, the upper margin of the ilium.

   Iliac passion. See Ileus.

   Iliac region, a region of the abdomen, on either side of
      the hypogastric regions, and below the lumbar regions.
      [1913 Webster]