Define what is meant by diverticular disease

Diverticular disease is herniation of mucosa through the muscularis of the colonic wall. It usually occurs at the site of relative weakness where mesenteric blood vessels pass between the taeniae coli through the colonic muscle wall.

What is the difference between a true and false diverticulum?

A true diverticulum contains all layers of the wall of the viscus (e.g., Meckel's diverticulum). A false diverticulum involves only some layers (e.g., colonic diverticulum).