deadlight

noun4

1. •
   A strong (often wooden) shutter fitted over a porthole, that can be closed in bad weather to keep water out and discourage the glass windows from breaking.
2. •
   A deck prism, a device to allow light into the cabin of boat through the deck.
3. •
   (figurative, no longer used) An eye.

   • Here you comes and tells me of it plain; and here I let him give us all the slip before my blessed deadlights! — 1881
4. •
   (figurative, no longer used) An eyelid.

   • He had one hand on the bounce bottle—and he'd never let go of that since he got back to the table—but he had a handkerchief in the other and was swabbing his deadlights with it. — 1913