What does my HW mean by saying Rice is the staple food for over half people in world?

The statement means that rice is the primary food source for more than half of the world's population. Rice is a versatile grain that can be grown in a variety of climates and is a major part of the diet in many countries, particularly in Asia and Africa. It is estimated that over 3.5 billion people rely on rice as their main source of nutrition, making it one of the most important crops in the world.