Diverticulosis: Diverticulosis is the condition of having diverticula, small outpouchings from the large intestine, the colon. (One outpouching is a diverticulum; two or more are diverticula).Diverticulosis can occur anywhere in the colon but it is most typical in the sigmoid colon, the S-shaped segment of the colon located in the left lower part of the abdomen.iverticulosis: Diverticulosis is the condition of having diverticula, small outpouchings from the large intestine, the colon. (One outpouching is a diverticulum; two or more are diverticula).