| A | B |
|---|
| silt | a mixture of tiny bits of soil and rock carried and deposited by a river |
| drought | a long period of dry weather |
| levee | a wall built along a riverbank to prevent flooding |
| irrigation | the watering of dry land by means of canals or pipes |
| erosion | the gradual wearing away of soil and rock by wind, glaciers, or water |
| cuneiform | a system of writing that used wedge-shaped symbols to represent sounds, ideas, and objects; developed in ancient Sumer |
| scribe | a professional writer who kept records and copied letters and official documents |
| city-state | a self governing city, often with surrounding lands and villages |
| ziggurat | a large pyramid with several stories built by the ancient Sumerians, Assyrians, and Babylonians |
| polytheism | the belief in many gods and goddesses |
| empire | a group of lands and peoples ruled by one government |
