Diner lingo has been used by diner employees and customers since the 1840s, and includes fun phrases like "Adam and Eve on a raft" (which means an order for two eggs on toast) or "Give it shoes" (AKA make the order to-go). One lesser-known lingo term is "radio," which is often used by diners to refer to a tuna fish sandwich.

In diner kitchens in the 1950s, workers would tell each other to "tune it" or "tune it down," telling others to turn down the radio in the kitchen. A customer or worker saying "tuna" can easily be misheard as "tune it," and this funny association stuck, so a tuna sandwich became known as a "radio" to diner regulars and staff.

An order for tuna on toast is also often referred to as "tuna down" or "radio down." The odd story of "tuna" to "radio" has been likened to the childhood game of telephone, in which a word or sentence is whispered to one person after another, passing down an entire line of people — and usually ends up mutated by the end.