Porthole

Part of speech: noun

Pronunciation: /ˈpɔː(ɹ)t.həʊl/

Definitions

1. A small circular opening in the side of a ship or aircraft that admits light and air and can be closed with a cover
2. A circular window fitted in the hull of a ship or aircraft, designed to provide light and ventilation while allowing for closure when needed
3. An opening in the side of a vessel or airplane that is round, permitting both illumination and airflow but featuring a cover for sealing

Etymology: "Porthole" is a plain compound of "port" and "hole," and its history is about the sea. The "port" here is the nautical term for a ship's left side, the side that faced the harbour when a vessel was docked, which is a different word from the "port" meaning a harbour town. The ship's side was once called "larboard," and "port" replaced it to avoid confusion with "starboard" when those words sounded too alike in a gale. Early ships needed openings in their hulls to let in light and air, and a round opening in the side of a vessel was a "port-hole," meaning a hole in the port side, though the term later came to be used for any such opening, on either side. Sailors also used the word for the openings through which cannons were fired, which is why a porthole can still bring a warship's gun ports to mind.

Synonyms: window, opening