A diner is a type of restaurant found across the United States and Canada, as well as parts of Western Europe. Diners offer a wide range of foods, mostly American cuisine, a casual atmosphere, and, characteristically, a combination of booths served by a waitstaff and a long sit-down counter with direct service, in the smallest simply by a cook. Many diners have extended hours, and some along highways and areas with significant shift work stay open for 24 hours.

A greasy spoon is a small, cheap restaurant typically specializing in short order fare.