cheese single

Probably from the brand Kraft Singles, from single (“individual”).

cheese single (plural cheese singles)

1. A prepackaged individual slice of processed cheese.
   • 2006, Jarod Kintz, E-mails from a Madman: Namdam a Morf Sliame:

     Like a cheese single, there can be only one. Down with your monarchy of mass-produced hamburgers.

   • 2021, Aku-Petteri Korhonen, Trekking over the Alps, page 52:

     You can order a standard breakfast from the menu, which is three pieces of bread and a cheese single, jam, a pasty, honey, butter and a cup of coffee.

   • 2022, David Rachlin, Billy Backside and Other Stories:

     Sally and Lynn sat at the butcher block table in the kitchen and fixed tuna salad sandwiches with a cheese single and a pickle on wheat bread.