Clairvoyance, produced from a 17th Century term which means clear vision, is a form of ESP - Extra Sensory Perception. Although frequently used to describe many different psychic abilities, for example second sight, telepathy, prophetic ideas and psychic dreams, it is strictly speaking the capability to discern information about a person, object, area or event by means of perception other than through the usual five sensory faculties. A person gifted with this particular ability is called a email - a person who views clearly.
In parapsychology, the phrase clairvoyance is used purely to spell it out information - in the the present time and not necessarily readily accessible to the particular clairvoyant - received from an external source, instead of telepathy, where information is transferred from one mind to another. In other words, a email has the ability to see or even visualise events, objects or persons outside of the capability or array of physical sight.
Distant viewing, usually a controlled, specific process, is really a facet of voyance gratuite, as is email dreaming. For instance, a person may dream about a location they've never seen before and later on find it is exactly because they had visualised it inside their dream.
This became of me, for example, after i was about to start my personal first term at school. As I had never visited the city where the school was located, my pops offered to take me personally there in order to find the way from the train station for the college. Having dreamed about it the night before we went, I used to be able to lead him to the school along the shortest route possible, knowing wherever and when to turn. I was even able to make sure he understands how long it would take us to get right now there.
However, outside of the field of parapsychology the term is often used to describe other types of paranormal, or anomalous, perception. Generally, it is used in regards to the perception of earlier (retro cognition) or perhaps future (precognition) events. This is a gift many have without even realising it. To use another personal expertise as an example (and I don't claim to be a clairvoyant in any way), a few years ago, the friend's daughter had gone into hospital at the start of the evening to have the girl first child. Whilst with a group of shared friends around 10 PM, someone suggested we should call the hospital and find out exactly how she was making. As one of them picked up the phone, I announced that a call will be wasted, as she would have a little boy in the early hours of the subsequent morning. We called anyway and were advised she was asleep as the labour experienced slowed. My friend informed me the next morning which her grandson came to be at 5:30 AM.
Frequently, mediums will also refer to the actual perception of images perceived during communication along with spirits as clairvoyance.
Whatever the case, clairvoyance is a precious reward which can and should be used in order to help and guide others.