1982, often as two words at first, coined by science fiction writer William Gibson (best known for "Neuromancer") and used by him in a short story published in 1982, from cyber- (see cybernetics) + space (n.).
The space in which computer transactions occur, particularly transactions between different computers. We say that images and text on the Internet exist in cyberspace, for example. The term is also often used in conjunction with virtual reality, designating the imaginary place where virtual objects exist. For example, if a computer produces a picture of a building that allows the architect to “walk” through and see what a design would look like, the building is said to exist in cyberspace.