diverticulum
Medical term for a small pouch or sac protruding from the wall of a hollow organ, especially in the digestive tract.
A colonic diverticulum is a small pouch-like protrusion that forms in the wall of the large intestine.
diverticulitis
Standard kanji form for this medical term.
From 憩 (rest, recess) and 室 (chamber, room), likely a calque from Western medical terminology.