Recreation room

A recreation room or rec room was a space in a starship where crew could relax while off-duty. A larger space with facilities for games or sports was referred to as a rec deck. Rec rooms might have food slots or replicators.

Rooms reserved for eating might instead be called a mess hall or wardroom.

Unused cargo bays were used as informal rec decks on the USS Mumbai. There was an officers' lounge at the aft of the saucer section with a cocktail bar. 

Ships of the had a two-decks-tall rec deck with external windows. 

The USS Enterprise (NCC-1701) had several small rec rooms. After the refit it also had a large rec dec on deck 7, where James Kirk delivered his V'ger briefing, and an officers' lounge. (TOS, )