Definitions

1. adverb

moving or directed in the direction of a river’s flow, especially from a point upstream to a point downstream.

“The raft drifted downriver, its course changing with the current.”

2. noun

the lower part of a river’s course, especially from a point upstream to a point downstream.

“The city lies at the mouth of a river, near the downriver end of its delta.”

3. adverb

moving or directed towards a place downstream, especially from a point upstream.

“The hikers were going downriver to explore the riverbank.”