River regime refers to the pattern of flow in a river over time. Synonyms for river regime include stream pattern, flow variability, and hydrological cycle. Flow regime and hydrograph are also commonly used terms to describe the fluctuations in a river's water levels. Water cycle, or the way in which water moves through the environment, can also be a synonym for river regime, as it involves the same processes of precipitation, evaporation, and water flow. Understanding a river's regime is essential for managing water resources, predicting flooding, and managing ecosystems that depend on a stable flow of water.