What is the X in X-mas?
ileitis il·e·i·tis (ĭl'ē-ī'tĭs)
Inflammation of the ileum.
chronic inflammation of one or more sections of the intestine. In its strict sense, the term refers to an inflammation of the lower, or terminal, portion of the small intestine, known as the ileum. A specific and more serious type of inflammation involving both the small and large intestines is known as regional ileitis, or Crohn disease.