Maize (called corn in some countries) is Zea mays, a member of the grass family Poaceae. It is a cereal grain which was first grown by people in ancient Central America. It is now the third most important cereal crop in the world. However, little of this maize is eaten directly by humans.Maize, also known as corn, is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences and separate ovuliferous inflorescences called ears that yield kernels or seeds.