A Lantern

1. A case of translucent or transparent material made to protect a flame, or light, used to illuminate its surroundings.
2. (theater) Especially, a metal casing with lens used to illuminate a stage (e.g. spotlight, floodlight).
3. (architecture) An open structure of light material set upon a roof, to give light and air to the interior.
4. (architecture) A cage or open chamber of rich architecture, open below into the building or tower which it crowns.
5. (architecture) 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
6. (engineering) A lantern pinion or trundle wheel.
7. (steam engines) A kind of cage inserted in a stuffing box and surrounding a piston rod, to separate the packing into two parts and form a chamber between for the reception of steam, etc.; a lantern brass.
8. (rail transport) A light formerly used as a signal by a railway guard or conductor at night.
9. (metalworking) A perforated barrel to form a core upon.
10. (zoology) Aristotle's lantern