Maize is corn. Although maize is the name of the many types of a tall grass called zea mays, North Americans know it as the sweet corn grown as food.
According to the International Institute of Tropical Agriculture, maize is a cereal crop that serves as a staple food source for more than 1.2 billion people in Africa and Latin America alone. It's also an important livestock feed. Ochef notes the term "corn" is rarely used throughout most of the world except to refer to corn-based products, such as syrup and oil. The Spanish, French, Italian and Germans refer to corn using some variation of the word "maize."