The term "wetted perimeter" refers to the boundary of a river, stream, or other body of water that is in contact with the fluid. There are several synonyms for this term, including waterline, water perimeter, and inundation boundary. These terms are often used interchangeably and can be applied in various contexts, such as hydrology, engineering, and environmental studies. The wetted perimeter is a critical parameter in these fields as it influences the flow of water and the interactions between water and the surrounding surfaces. Understanding the wetted perimeter is critical to managing water resources, designing water infrastructure, and predicting flood risks.