Final answer:
The direction of stream flow from higher elevations to lower elevations is referred to as downstream direction.
Step-by-step explanation:
The direction of stream flow from higher elevations to lower elevations is referred to as downstream direction. When water flows downhill, it follows a path of lower elevation and ultimately leads to a larger body of water, such as a river or ocean.
For example, when rain falls on a mountain and flows down the slopes, it joins other streams and rivers along its path and eventually reaches the sea. Similarly, when snow melts on a mountaintop, the resulting water will flow downhill towards lower areas.