What does tributaries mean in ancient Egypt?

In ancient Egypt, "tributaries" referred to smaller rivers or streams that flowed into larger bodies of water, particularly the Nile. These tributaries were crucial for irrigation and agriculture, providing the necessary water to support farming in the arid landscape. Additionally, the term can also denote regions or peoples that paid tribute to the pharaoh, contributing resources or goods in exchange for protection or favor. This system reinforced the power and wealth of the Egyptian state.