Refers to goods with average quality and broad market. Jiang Zilong's Pot Symphony: "I don't mean to sell high-end food, not staple food, but to study what is a best-selling staple food."
Word decomposition
The interpretation of "big" means that the area, volume, capacity, quantity, strength and intensity exceed the average level or the object being compared, as opposed to "small": hall. Great politics. The climate is very good. A cock is valiant on his own dunghill. Big belly. This room is as big as that one. Large scale, deep degree and important nature: the overall situation. common people