The word “cyber” was first used in the word “cybernetics,” coined by Norbert Wiener for the book of the same title printed in 1948. It is derived from the Greek for steersman, the idea being that both concepts are based on the idea of control.
Cyber became a prefix for anything related to computers or advanced mechanics. In the 1960’s the word cyborg was coined, becoming the first (and possibly only) word to omit the “er.” Several other uses such as cyberneticain and cybernition were coined throughout the seventies and eighties, the word cybernaught, appeared in a 1965 episode of the Avengers, but this is the only usage of it I have ever heard.
William Gibson invented the word Cyberspace in 1982 in his short story, Omni. It described an electronic realm similar to a virtual reality where your brain and body are linked directly to the computer, however it is now often a synonym for the internet. In soft or children's science fiction it is occasionally used to describe a world inside a computer in which everything is bright and zappy.
Currently there are around 2000 words that include cyber as a prefix, I am fairly sure I have recently seen The News of the World, or The Sun, or some other gutter-press tabloid use the term Cyberphile to describe a paedophile who uses the internet to bait young children. There is also cyberphobia which is a fear of electronic technology and is interesting since it uses the standard Greek prefix for phobias and in fact means “Fear of steersmen.”