Definitions include: a type of shareware that interrupts use of the software to display a message asking the user to "register" the software (i.e. pay for it.)
Definitions include: in the user interface of a software product (including websites,) something that displays the locations that the user has recently viewed or visited.
Definitions include: This theorem has been traced to the mathematician E'mile Borel in 1913, and was first popularized by the astronomer Sir Arthur Eddington.
Definitions include: Cyberspace is a term coined by the novelist William Gibson in his novel Neuromancer to describe existence in virtual reality (or loosely in the internet): "Cyberspace. A consensual hallucination experienced daily by billions of legitimate operators, in every nation, by children being taught mathematical concepts... A graphical representation of data abstracted from the banks of every computer in the human system. Unthinkable complexity.