Reflected light is a soft non-direct light that bounces from one surface to another. Unlike direct light, it tends to take on the colour of the surface it has reflected off of.
An example of how this works can be seen in the slot canyons in Arizona. When the sun is high in the sky, shafts of light stream through the small openings at the top of the canyons. That direct light then reflects onto an adjacent wall. The reflected light is less intense, fills in the shadows, and takes on the colour of the rock. When the canyon becomes very narrow, the light bounces back and forth many times and makes the rock appear to glow red.
Light reflecting off of water also creates dramatic results. The ideal situation for a water reflection is when there is direct light on a colourful subject and that subject is reflected in water which is in the shade. In this example, the setting sun lights the top of the mountain and creates a reflection in the mirror smooth water of the lake.
The subject receiving the direct light does not necessarily need to be in the frame. In this example, only the subject’s reflection is in the frame creating a more impressionist feel.
For a more abstract look, the frame may contain only the reflection with no other supporting elements to indicate the subject that is being reflected.
See my earlier post for more types of natural light that will drama to your photography.