18th Century word origin
M. Boulanger, signaling the post-revolutionary end of great aristocratic kitchens in France and the beginning of chefs making themselves commercially available for the masses, put a sign outside his Parisian soup restaurant in 1765, saying...
"Venite omnes qui stomacho laboratis, et ego restauranto vos."
[or, "Come all ye who labor with the stomach, and I will restore you"].
Thus today's word "restaurant" from restauranto.