A pilonidal cyst is a unique kind of abscess that occurs in or above the crease of the buttocks. Pilonidal cysts often begin as tiny areas of infection in the base of the area of skin from which hair grows (the hair follicle).
Cofferdam A cofferdam is a temporary enclosure built within, or in pairs across, a body of water and constructed to allow the enclosed area to be pumped out, creating a dry work environment for the major work to proceed.
Learner's definition of DAM. [count] : a structure that is built across a river or stream to stop water from flowing. The government has plans to build a dam and flood the valley. There's a beaver dam [=a dam built by beavers] in the stream behind my house. [+] more examples [-] hide examples [+] Example sentences [-] Hide examples. â compare 3dam.