1. An extended surface used to increase the heat transfer area, as metal sheets attached to tubes.
2. A thin flange projecting outward from the periphery of the frame of an aluminum window to serve as a means of securing the frame in a wood or masonry opening.
3. A narrow linear projection on a formed concrete surface, resulting from mortar flowing out between spaces in the formwork.
4. A thin projection on a casting or forging resulting from trimming or from the metal under pressure being forced into hairline cracks in the die or around die inserts.
5. A steel sheeting wall which projects from a main cofferdam structure.