If you place someone or something in an environment that causes them to experience something, you can call this exposure. Exposure to sun and rain will cause wood to turn gray. In school, you will be given exposure to the basic principles of math, science and language.
The exposure of film to light results in a photograph. Sometimes, exposure is used without explicitly saying what something or someone was exposed to. It is simply implied. When a celebrity is given lots of exposure, it is well-known that the media is involved. If you die of exposure, it's understood that the harsh elements of the weather was meant. And if your house has a southern exposure, you know that this is the side where the sun shines.