Weatherhead

Part of speech: noun

Definitions

1. A type of weather protection device designed to shield navigational equipment from the elements; a structural component used in maritime contexts to deflect rain and wind; equipment often seen on ships to enhance visibility and performance in adverse weather conditions
2. A protective feature that aids in safeguarding navigation instruments against environmental conditions; an element employed in boating that helps manage wind and precipitation; a fixture on vessels aimed at improving operational efficiency during storms
3. An accessory associated with nautical technology, made to cover sensitive equipment from harsh weather; a building part utilized in ships to resist the impact of rain and wind; a tool essential for maintaining functionality during inclement weather

Etymology: "Weather" comes from Old English "weder," which meant the air's conditions in general, and it gave English the nautical "weather side," the windward side of a ship or hill. A "weatherhead" joins that old word to "head," meaning the top or upper end of something. The compound is most plausibly a term for the exposed top of a structure facing the elements, though its earliest recorded uses are hard to pin down precisely. In modern usage, the term most often names a fitting at the top of a vertical pipe or electrical service mast, shaped so that rain runs off and water cannot drip into the line below. The maritime sense given in your context, a deflector for navigational equipment, is not one I can confirm from standard references.