Five grains refer to: rice, wheat, soybeans, corn, and potatoes. At the same time, grains other than rice and flour are also customarily called miscellaneous grains, and grains and grains also generally refer to food crops, so grains are also grains. A collective name for crops.

The earliest record of the term "grains" can be found in "The Analects of Confucius". According to the record in The Analects of Confucius: More than 2,400 years ago, Confucius took his students on a long trip. Zilu was lagging behind. He met an old farmer carrying a bamboo basket with a staff and asked him, "Have you seen the Master?" The old farmer said: "If the limbs are not working and the five grains cannot be distinguished, who is the Master?"

Wu Gu means five kinds of grains. Books older than "The Analects" such as "The Book of Songs" and "The Book of Books" only mention "hundred grains" and nothing about "five grains". From hundreds of grains to five grains, have the types of food crops been reduced? No. In the past, people often gave a proper name to several different varieties of a crop, which made the list too much. Moreover, the word "hundred" here is just used to mean many, and there are not really a hundred kinds. The emergence of the term "grains" indicates that people have a relatively clear concept of classification, and also reflects that there were five main food crops at that time.