Cyberspace

"Cyberspace. A consensual hallucination experienced daily by billions of legitimate operators, in every nation, by children being taught mathematical concepts. … A graphic representation of data abstracted from banks of every computer in the human system. Unthinkable complexity. Lines of light ranged in the nonspace of the mind, clusters and constellations of data. Like city lights, receding."

• Quote by William Gibson, popularized by Neuromancer in 1984, though he first published it in Burning Chrome, 1982.

• Additional definitions here: http://project.cyberpunk.ru/idb/cyberspace.html