The word Séance originally came from the old French word seoir : 'to sit'. The word evolved into the French word séance, which means 'seat', or 'session'. Initially it has been used for meetings in general, but later came to be used specifically for a meeting of people to receive spiritualistic messages (a sense first recorded in English in 1845).
In the past these meetings were sometimes called 'circles', because participants, called 'sitters', sat around a table (or on chairs arranged in a circle) in order to link hands, in the belief that this boosted the psychic forces which encourage paranormal manifestations.
The normal human way of thinking is that we are part of something more then what is visible in our physical 3-dimension reality. We envision gods, angels, ghosts, spirits, and others on the other side that sometimes interact in this realm. Humanity has always intended to connect with their creators - who are thought to exist above this realm.
A séance generally involves communication between the physical realms and one or more entities in other dimensions. The person who contacts 'the other side' is often referred to as a medium. Modern psychic researchers and mediums prefer the term 'sitting'.
The history of séance communication can be traced back to the third century. Seances were often related to occult practices bringing fear to those who attended or heard about them.
To many people, the concepts of spirits residing 'on the other side' that can communicate with us seem impossible to comprehend and therefore these people tend to think in terms of black ceremonial rituals, magic or deceit.