Mess hall

A mess hall is a place on Federation and Klingon starships or starbases where one can relax and enjoy a meal or a quick snack in a social setting.

It is also the place where officials, such as ambassadors of other worlds, are entertained. Gatherings are also held there.

A mess officer was in charge of activities within the mess hall. 

NX-class
Earth Starfleet starships of the 22nd century were outfitted with large mess halls located on the starboard side of E Deck. Boasting several large windows, the NX-class mess hall was a buffet-style environment; food prepared in the ship's galley was brought to the mess hall and stored in a refrigerated display case located on a bulkhead adjacent to a beverage dispenser. Aboard the starship, the mess hall was converted into a theater on some Tuesday nights for "movie night". A large screen was erected in the mess hall, controllable from bridge stations on A Deck.

Located just aft of and connected to the mess hall was the captain's mess. 

Defiant-class
Like much of the internal spaces aboard starships, the mess hall was compact, functional and had no windows. It was equipped with one food replicator. The mess hall could also be used for meetings with the ship's crew. 

Worf often ordered prune juice in the mess hall of the Defiant. Once, he received a cup advertising Quark's. 

In 2372, Dukat and members of the Detapa Council underwent blood screenings in the mess hall after being rescued by the Defiant.

Several weeks later, the mess hall was the site of a meeting between Captain Sisko, Quark and Hanok. Later, a Jem'Hadar torpedo impacted into the mess hall, but did not explode immediately. Quark and Hanok were able to defuse it. 

Later that year, the mess hall was the site of a briefing session between the crew of the Defiant and Weyoun's Jem'Hadar soldiers. 

During the early months of the Dominion War, the crew would place depleted phaser relay power cells in the mess hall as a sign that they would never stop fighting. 

Ixtana'Rax had the senior staff of the Defiant held in the mess hall after the Jem'Hadar briefly captured the starship in 2374. 

Quark was ordered to stay in the mess hall as the Defiant fought its way to AR-558 in 2375. 

Intrepid-class
On vessels, the mess hall is on Deck 2, Section 13, with turbolift access in the corridor outside the starboard entrance. Some ships were equipped with four food replicators, with a private captain's dining room just behind the mess hall. The dining room could be reconfigured, and two of the replicators removed, to serve as a kitchen, as was done by Neelix aboard the USS Voyager. The USS Bellerophon (NCC-74705)'s mess hall was also fitted in this manner. 

Since replicator rations were in short supply aboard Voyager, Neelix supplemented food stocks with vegetables from the airponics bay along with food obtained from trading and scouting missions.

The mess hall aboard Voyager was host to many social gatherings, including diplomatic affairs, birthday parties,  ping pong games,  and holiday celebrations. 

When Neelix departed Voyager in early 2378, Chell wanted to take over duties in the mess hall. The ship returned to the Alpha Quadrant shortly following, and it is not known if Chell was given the position. 

The mess hall also served as a makeshift sickbay whenever that facility was disabled or otherwise overwhelmed. 

Klingon Bird-of-Prey
Several Klingon Birds-of-Prey – such as the, the , and the –  were known to include mess halls. 

In 2373, a fight involving Kornan, Leskit, and Ortakin broke out in the mess hall of the Rotarran. 

When Alexander Rozhenko joined the crew of the Rotarran, he was mocked by Ch'Targh and others in the mess hall. 

In early 2375, Miles O'Brien, Julian Bashir, and Quark ate gagh in the mess hall of the Rotarran. Quark complained about the lack of a variety of foods.