Wiktionary
n. A room on an aircraft carrier where on-duty pilots are stationed while not flying their aircraft.
Wikipedia
A ready room is a room on an aircraft carrier where on-duty pilots "stand by" their airplanes. Each flight squadron has its own individual ready room. Large squadrons, such as torpedo and dive-bomber squadrons, can have more than one ready room. Most ready rooms are located between the flight and hangar decks, but some are located on the flight deck.
Squadron pilots in the Second World War considered the ready room to be a clubroom. One personal view from a World War II pilot stated:
Usage examples of "ready room".
Captain Harmon inquired genially as she used an old-fashioned, nonilluminated pointer to gesture at the frozen holo display above the ready room tac table.
We suited up in the ready room while Nugget coordinated tracking and ESRB relay through SAR Command at L-4.
When he reached his ready room, the first one he placed was to Admiral Noguchi.
Ding asked, after getting his wife bedded down in the unused ready room.
Seconds later they were inside, with Christopher, Winward, and Link waiting for them in the ready room.
The both of them got scanned for alien life-forms, were pronounced clean, and allowed to wait in the ready room or head into one of the galleys to get something to eat.