A sit-down restaurant is simply a restaurant that caters to customers who plan to sit down and be served by waitstaff. Historically called simply restaurants, following the rise of fast food and take-out restaurants, a retronym for the older "standard" restaurant was created. Sit-down restaurants are often further categorized as "family-style" or "formal".
Example Usage of restaurant
Fleurs22: @THEREALDWELE Hot and Sour soup from your favorite or best Chinese restaurant always works best when you are sick. If you can take the heat!
imohkay: Govinda restaurant, near the ISKCON temple. Delicious veg fare. the most amazing cream cheese dosas, good pizza & Indian fare!
xDEvelynxD: ♪We be at the club, the restaurant, the grocery store or the movies
Kissing and touching with my hands all over your booty♪ @backstreetboys