A restaurant is an establishment that serves food to customers.
Joseph Sisko owned and operated Sisko's Creole Kitchen, a restaurant in New Orleans. (DS9: "Homefront", "Paradise Lost", "Image in the Sand")
One of the many function of Quark's on Deep Space 9 was to serve as a restaurant for the occupants and visitors to the station. (Star Trek: Deep Space Nine)
In an holodeck program launched by one of the RIS Bouteina's EMHs, Florina (herself an EMH) had a husband that opened a restaurant of salt-free cuisine. (RIS Bouteina: "Holographic Family")
During a visit on 43 Lindum, Taev Radaik, among others, have eaten for thirty days at a single fast food restaurant called Turbo Pizza. (RIS Bouteina: "Super Size Me", "Super Size Me Again")
Restaurant article at Memory Alpha, the canon Star Trek wiki.