Wiktionary
n. the totality of information, especially that which is accessible online
Wikipedia
Information space is the set of concepts and relations among them held by an information system; it describes the range of possible values or meanings an entity can have under the given rules and circumstances.
Another definition (idealistic) is that the information space are the total results of the semantic activity of the humanity, "the world of names and titles", conjugated to the ontological world. Being a primary concept, the information space cannot be precisely defined and is set as a dialectical opposition to the material, physical, object space.
Max H. Boisot, also writes a book on Information Space: A framework for learning in organizations, institutions and culture. In his book, Boisot (1995,p. 5) describes information space as a conceptual framework or tool for studying how knowledge and information are codified, abstracted and diffused through a social system.
Usage examples of "information space".
Unexpected fringe-riders are developing new ecological niches on the edge of the human information space, light-minutes and light-hours from the core, as an expansion that has hung fire since the 1970s gets under way.