deadlight

1. (nautical) 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. (nautical) A deck prism, a device to allow light into the cabin of boat through the deck.

3. (figurative, archaic) An eye.Examples: "Here you comes and tells me of it plain; and here I let him give us all the slip before my blessed deadlights!"archaicfiguratively

4. (figurative, archaic) An eyelid.Examples: "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."archaicfiguratively