Going down is a term that can refer to a variety of different activities. DESCENT, which has seven letters, is the act of moving from a higher to a lower level, such as when descending a staircase or a mountain. SINKING, also with seven letters, is the process of gradually going lower in level, such as when a boat sinks in water. SETTING, also with seven letters, is the process of gradually becoming lower, such as when the sun sets in the evening. Orup, with four letters, is a term used to describe the gradual lowering of a river's bed due to erosion.