Clairvoyance, derived from a 17th Century term that means clear vision, is a type of ESP - Extra Sensory Perception. Although usually used to describe a variety of psychic abilities, for example second sight, telepathy, prophetic visions and psychic desires, it is strictly speaking the power to discern details about a person, object, area or event by means of perception other than through the usual five senses. A person gifted with this particular ability is called a email - a person who views clearly.
In parapsychology, the word clairvoyance is used purely to explain information - both in the present time and not really readily accessible to the clairvoyant - received from an external source, rather than telepathy, where information is transferred from one mind to a new. In other words, a clairvoyant has the ability to see or visualise events, items or persons outside the capability or range of physical sight.
Remote viewing, usually a managed, specific process, is 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 as they had visualised it in their dream.
This happened to me, for example, when I was about to start my first term in school. As I had never frequented the city where the college was located, my Father offered to take myself there in order to find the way in which from the train station for the college. Having dreamt about it the night before we went, I had been able to lead him to the faculty along the shortest path possible, knowing in which and when to turn. I was even able to simply tell him how long it would take us to get there.
However, outside of the area of parapsychology the term is generally used to describe other types of paranormal, or anomalous, perception. Most of the time, it is used in relation to its the perception of earlier (retro cognition) or perhaps future (precognition) events. It is a gift many have got without even realising that. To use another knowledge 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 early in the evening to have her first child. Although with a group of mutual friends around 10 PM, somebody suggested we should phone the hospital and find out just how she was making. As one of them picked up the phone, I declared that a call could be wasted, as she would have a little boy during the early hours of the subsequent morning. We called anyway and were advised she was in bed as the labour had slowed. My friend said the next morning that her grandson was created at 5:30 AM.
Frequently, sources will also refer to the 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 also guide others.