Conceptual integration - also known as "blending" is a basic mental operation whose uniform structural and dynamic properties apply over many areas of thought and action, including metaphor and metonymy. Conceptual integration creates networks of connections between mental spaces. Some of these mental spaces serve as inputs to a new, blended mental space that typically develops emergent meaning not contained in the inputs. In the case of metaphor, a source and a target serve as inputs to the blend. Creating the blend often involves the exploitation of metonymies. (Mark Turner and Gilles Fauconnier)