Dysphemism

Nowhere are they more common than in the argot of the greasy spoon (a dysphemism for the word “diner”), immortalized in the 1941 book by Jack Smiley, “Hash House Lingo”. Toast was called a board or a shingle; tea was boiled leaves and coffee was mud; bullets were baked beans, and a steak, well-done, was a burned steer.

Merriam-Webster