QSR stands for Quick Service Restaurant, which is a type of restaurant that offers fast food or fast casual dining. QSRs typically serve food that is prepared and served quickly, with a focus on convenience and affordability. Customers order at a counter or drive-thru and take their food to go, or eat in a limited seating area. Examples of QSRs include fast food chains such as McDonald's, Subway, and KFC, as well as fast casual restaurants such as Panera Bread and Chipotle Mexican Grill.

QSRs have become increasingly popular in recent years due to factors such as the busy lifestyles of consumers and the growing demand for convenient and affordable food options. This has led to a highly competitive market, where QSRs must differentiate themselves and offer high-quality food and customer experiences in order to succeed.