Deadlights

Part of speech: noun

Definitions

1. A type of heavy canvas or tarpaulin used on ships to cover portholes and prevent water from entering during storms
2. A solid shutter or cover for openings in a vessel, designed to protect against flooding
3. Protective coverings or barriers for portholes that safeguard the interior from harsh sea conditions and water damage

Etymology: The word "deadlights" is simply the plural of "deadlight", a nautical term for the solid metal cover fitted over a ship's porthole or window in heavy weather. The singular is formed from "dead" and "light", and the compound is easy to parse: a light that is shut off, blind, or unable to let in daylight. The "dead" element here carries the sense of something deprived of its usual function, much as a "dead calm" is a calm with no wind at all. The plural form is the usual one in speech, since a ship typically had several such covers, but the term is used with the same meaning in both numbers. Sailors would hear the call to secure the deadlights as a sign that a storm was serious enough to shutter the ship's openings against breaking seas.