The name of a popular high school
cafeteria item. Usually means
roast beef, with
gravy, on soggy white bread.
The
open face part is because the two pieces of bread are separate, at the bottom, under the meat and gravy.
Not only is this rarely tasty, it is a source of amusement for many students who often stare at the kitchen help and hold their mouths open wide when told what the meal is called.
Large, sweaty kitchen ladies in formerly white uniforms do not find this amusing in the least.