What does "Shit on a shingle" mean?

If you hear a waitress say "Shit on a shingle" at a diner or restaurant, it's just another way to say "Chipped beef with gravy on toast." Also referred to as "S.O.S." It was once known as a bland staple of army mess halls. There are hundreds of other popular diner lingo phrases - to learn more, check out the links below or browse the rest of our restaurant slang dictionary.