cut-out

n. (a) 1. (Telegraphy) A species of switch for changing the current from one circuit to another, or for shortening a circuit. (b) (Elec.) A device for breaking or separating a portion of circuit. [ 1913 Webster ]

2. Something cut out from another object, especially a piece of thick paper or cardboard with a picture on it (as of a person or other object), embedded in a larger sheet of paper and having perforations around the edges of the figure to allow easy removal from the larger sheet. [ PJC ]

3. A valve in the exhaust system of an internal combustion engine which, when activated, permits the exhaust gases to bypass the muffler. [ PJC ]