ileum
[C] Countable
pl: ilea
This term is strictly medical and anatomical, used primarily by healthcare professionals, biologists, and students of medicine. It describes a specific physical location in the digestive tract where the absorption of vitamin B12 and bile salts occurs. It is frequently confused with the word ilium, which refers to the upper part of the hip bone. While they sound identical, the ileum is a soft tissue organ of the gut, whereas the ilium is a hard bone of the pelvis.
Countable when referring to the specific anatomical organ in an individual or multiple patients.