Lanthorn

noun

1. A case of translucent or transparent material made to protect a flame, or light, used to illuminate its surroundings.
2. Especially, a metal casing with lens used to illuminate a stage (e.g. spotlight, floodlight).
3. An open structure of light material set upon a roof, to give light and air to the interior.
4. A cage or open chamber of rich architecture, open below into the building or tower which it crowns.
5. A smaller and secondary cupola crowning a larger one, for ornament, or to admit light.

   "the lantern of the cupola of the Capitol at Washington, or that of the Florence cathedral"