shutter

1. Scenic. noun.
a) louvered panel (usually in pairs) on windows that allows air circulation but protection from the elements.
b) the operable/moving part of any door/window.

2. Camera/projection, and moving light. noun. Mechanism that blocks the gate and prevent light from entering/exiting. Similar to douser.

3. Conventional lighting.
noun. Short for "framing shutter," a blade (usually one of four) at the gate of an ERS or profile spotlight that allows beam shaping.
verb. To use the above: "Shutter off the proscenium."