An information space is a data set navigable by means of an associated or embedded decision tree by use of programs. Sometimes refers to the visualation of such combinations into relational mappings.

Information space: a set of items and relations among items. For information systems, an information space might consist of a set of TERMS and DOCUMENTS, each of which is related to one another.

Unlike a hierarchy, tree, semantic network, or&other data structure, information spaces are fully relational: everything is related to everything else. This makes visualization difficult (there's no inherent structure) but very interesting and rich.