| A | B |
|---|
| Basin | The area containing all the streams and watercourses of one river. |
| Civilization | An advanced stage of human social development which usually includes a formal gathering place for social and cultural activities, a system of writing, and a city. |
| Delta | A landform that is formed at the mouth of a river, where the river flows into an ocean, sea, estuary, lake, or reservoir. Deltas are formed from the deposition of the sediment carried by the river as the flow leaves the mouth of the river. |
| Deposition | Where material is put down. |
| Divide | A ridge of land that separates two adjacent river systems. |
| Downstream | The area nearer to the mouth of the river. Moving in this direction would be with the flow of the river. |
| Erosion | The wearing away and removal of material. |
| Evapotranspiration | Where trees and plants take water out of the soil and pass it into the air, combined with the effects of evaporation from leaves and the ground itself. |
| Floodplain | The flat area stretching out from each side of the river, which may flood during springtime with heavy rains or snow melting. The soil is often rich because the flooding of the river deposits minerals and nutrients into the soil, making this area good for agriculture. |
| Irrigation | Supplying (dry land) with water by means of ditches, pipes, or streams. |
| Main River | The primary channel in a river. |
| Meander | A loop or bend in the river, as the water winds back and forth instead of in a straight line. |
| Overland Flow | Water moving on the surface towards a river. |
| River civilization | An agricultural (farming) nation or civilization based around rivers. |
| River mouth | Where a river flows into the sea, river, lake, reservoir or ocean. |
| River | A large natural stream of water flowing in a channel to the sea, a lake, or another such stream. |
| Riversource | The beginning of a river, often found in the mountains where melting snow or rain begins to flow down pulled by gravity. The source may even be an underground spring. |
| Saturation | When the ground is so full of water it cannot take in any more. |
| Tributary | Small rivers or streams that join and flow into a larger river. |
| Upstream | The area nearer to the source of the river. Moving in this direction would go against the flow of the river |
| Water Cycle | The processes by which water circulates between the earth's oceans, atmosphere, and land, involving precipitation as rain and snow, drainage in streams and rivers, and return to the atmosphere by evaporation and transpiration. |
| Waterfall | A place where water drops from a steep point in a stream or river |
| Watershed | An area or ridge of land that separates waters flowing to different rivers, basins, or seas. |
| Wetlands | Low-lying areas on both sides of a river that is so saturated with water, special vegetation has adapted to the wet conditions. |
