Mental spaces are regions of conceptual space that contain specific kinds of information. They are constructed on the basis of generalised linguistic, pragmatic and cultural strategies for recruiting information.

The hallmark of a mental space, as opposed to other cognitive entities such as a conceptual metaphor, a semantic frame, an idealised cognitive model or a domain (1), is that mental spaces are constructed 'online', in the moment of speaking or thinking, and can be structured by other cognitive entities including semantic frames, idealised cognitive models or domains by a process known as schema induction. Thus a mental space results in a unique and temporary 'packet' of conceptual structure, constructed for purposes specific to the ongoing discourse. The principles of mental space formation and the relations or mappings established between mental spaces have the potential to yield unlimited meanings. Mental spaces are set up by space builders, and can contain one or more of the following sorts of information type: an element, a property and a relation. Mental space construction begins with the formation of a base space relative to which other mental spaces are built. A series of connected mental spaces are referred to as a mental spaces lattice.