Downstream means in the direction that a river or stream flows, toward its end point rather than its source. If you drop a stick in a creek, it floats downstream toward wherever the water is going. A town located downstream from a factory sits farther along the river's path, in the direction the current moves.

The word also describes things that happen later in a sequence or process. In a factory, downstream work happens after earlier steps are complete. If a problem occurs upstream in production, it creates downstream effects: mistakes made early cause trouble later. When scientists study pollution, they track how chemicals move downstream through rivers and how problems spread downstream through food chains.

You'll hear people talk about downstream consequences, meaning results that show up later because of earlier choices. If you skip studying for weeks, the downstream consequence might be struggling on your final exam. In business, a company's decisions create downstream impacts for workers, customers, and communities.

The opposite is upstream, which means toward the source or earlier in a process. A salmon swimming upstream fights against the current to reach the place where it was born.