The sound made by a waterfall is commonly referred to as "waterfall noise" or "waterfall sound." It is a soothing and continuous sound produced by the flowing water as it cascades over rocks and falls to a lower level. The sound of a waterfall is often described as a steady, rushing or roaring noise, which can vary in intensity depending on the size and height of the waterfall. Many people find the sound of a waterfall to be relaxing and calming, often used for meditation, sleep, or as a natural background noise for relaxation purposes.