The term 'diner staple' refers to classic dishes that are commonly served in diners. These dishes include PIE (3 letters), eggs (4 letters), BACON (5 letters), HASH (4 letters), and omelet (6 letters). PIE is a baked dish made of pastry dough filled with sweet or savory ingredients. Eggs are a versatile food that can be cooked in many different ways, such as scrambled, poached, or boiled. BACON is a type of cured pork that is usually fried or grilled. HASH is a dish made of potatoes and other vegetables, often with meat added. An omelet is a dish made of beaten eggs cooked in a pan and filled with various ingredients. All of these dishes are popular choices at diners and are considered diner staples.