Wardroom
A wardroom was a multipurpose room, usually used by senior commissioned officers as a mess or function room.

The  had a wardroom, which was used to entertain visiting dignitaries. Charlie Evans walked past a wall sign that read "Ward Room B4" just before he transformed a young woman into an old lady crewwoman because he thought she was laughing at him. () The wardroom was also used, with stewards in attendance, when the Enterprises senior officers entertained Khan Noonien Singh to welcome him to the 23rd century. ()

In a similar fashion, the  also had a wardroom, called the mess hall or officer's mess. It was used to entertain Chancellor Gorkon and his party in 2293, after the Klingon moon, Praxis, had exploded. ()

In addition, Romulan  warbirds had a wardroom which was located to the starboard rear of the bridge. It was used as a private dining room for the ship's commander and senior officers. ()

Deep Space 9 also had a wardroom which was used in a similar fashion to a briefing room on Starfleet vessels, though its large area allowed it to be used for a variety of other purposes. While used by Benjamin Sisko to brief his officers, it was also used during events such as the Bajoran Gratitude Festival, Jadzia Dax's zhian'tara, and Sisko's promotion to captain. ()

In 2371, Gul Dukat was briefed in the wardroom by Odo and Commander Sisko about the stolen  and the actions of Maquis operative Thomas Riker. ()

Rom and Leeta's wedding ceremony and reception, Sisko's posting of casualty lists during the Dominion War, and the signing ceremony for the treaty that ended the war also took place in that room. ()

Unlike many other parts of the station, which maintained their Cardassian era displays, the wardroom contained an LCARS display monitor. During the Dominion occupation of the station the wardroom's display was replaced by a Cardassian-style display. ()

Appendices

Background information 
The TOS wardroom was a redress of the briefing room, while the Undiscovered Country wardroom was a re-dress of the  observation lounge.

The DS9 wardroom made its first appearance in the third season premiere, . However, its appearance in  indicates that the wardroom existed on Terok Nor during the Bajoran Occupation. The set was built on Paramount Stage 4. Noted Rick Berman, "The feeling was that it would be worthwhile to develop a set that would be similar to the observation in Next Generation." (Captains' Logs: The Unauthorized Complete Trek Voyages, p. 340)

In the British Royal Navy, the wardroom is the mess cabin of naval commissioned officers above the rank of sub-lieutenant. It is a place where these officers can relax when off-duty, though there is a strict etiquette to be followed. The captain of the ship is not usually a member of the wardroom, though can be invited in by its members.

External links 
 
 

de:Offiziersmesse
Station sections
Spacecraft sections