snub. (mining engineering). To increase the height of an undercut by means of explosives or otherwise. To check the descent of a car by the turn of a rope around a post.
Sessile polyps simply mean that the mass is flat and does not have a stalk. The other types of colonic polyps are pedunculated- these are not flat but attached to a stalk. Since a sessile colonic polyp does not have a stalk, it is usually found very close to the colonic wall lining.
A peduncle is an elongated stalk of tissue. Sessility is the state of not having a peduncle; a sessile mass or structure lacks a stalk. In medicine, a mass such as a cyst or polyp is said to be pedunculated if it is supported by a peduncle.