Clairvoyance, produced from a 17th Century term meaning 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, location or event via perception other than from the usual five senses. A person gifted with this ability is called a email - a person who views clearly.
In parapsychology, the term clairvoyance is used purely to describe information - both in the present time and not really readily accessible to the actual clairvoyant - caused by an external source, as opposed to telepathy, where information is transmitted from one mind to a new. In other words, a clairvoyant has the ability to see or visualise events, objects or persons outside of the capability or selection of physical sight.
Remote viewing, usually a managed, specific process, is a facet of voyance telephone espoir, 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 within their dream.
This happened to me, for example, when I was about to start my first term in school. As I had never been to the city where the university was located, my Father offered to take myself there in order to find the way in which from the train station to the college. Having imagined about it the night prior to we went, I was 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 presently there.
However, outside of the industry of parapsychology the term is often used to describe other types of paranormal, or anomalous, perception. Generally, it is used in relation to the perception of past (retro cognition) or future (precognition) events. This can be a gift many possess without even realising this. 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 choose to go into hospital early in the evening to have her first child. Although with a group of common friends around 10 PM, someone suggested we should call the hospital and find out just how she was getting on. As one of them picked up the phone, I declared that a call would be wasted, as she had have a little boy in early hours of the following morning. We known as anyway and were told she was sleeping as the labour acquired slowed. My friend informed me the next morning which her grandson was created at 5:30 AM.
Frequently, mediums will also refer to the actual perception of images recognized during communication together with spirits as clairvoyance.
In any case, clairvoyance is a precious gift which can and should be used in order to help and guide others.