In conceptual metaphor theory the source domain is the domain (2) which provides structure by virtue of metaphor. This is achieved by cross-domain mappings projecting structure from the source domain onto the target domain thus establishing a conventional link at the conceptual level. For instance, in the metaphor love is a journey, as evidenced by examples such as: This relationship is going nowhere, Our relationship is stuck in the mud, journey is the source domain.

space A fundamental conceptual domain (1/2) employed in conceptual metaphor theory, cognitive grammar, the conceptual structuring system approach and principled polysemy. The domain of space consists of matter which can be continuous or discrete, and locations occupied by matter. The nature of this domain derives from mechanisms central to perception which provide sensory experience thereby facilitating apprehension of physical aspects of our external physical environment.