- Urbatecture
- A portmanteau coined by Schuiten and Peeters to describe the total integration of urban planning, architectural design, and social engineering. In the Obscure Cities, the built form does not merely house human activity — it dictates it, creating a feedback loop between structure and consciousness.
- Bruxellisation
- The haphazard post-war redevelopment of Brussels that systematically demolished historic Art Nouveau landmarks (including Victor Horta's Maison du Peuple) in favour of anonymous office complexes. Schuiten's childhood observation of this process formed the reactive genesis of his entire aesthetic philosophy.
- Psychetecture
- Environments that reflect the mental and political state of their inhabitants. Each Obscure City functions as an externalised psyche — its architecture the visible symptom of a collective ideology taken to its structural extreme. Buildings in these cities can be carnivorous, totalitarian, or liberated, depending on the ruling principle of their urbatects.
- Urbatect
- An architect-planner-social engineer who wields total authority over a city's physical form and, by extension, its population's psychology. The urbatect is often the tragic hero of the Obscure Cities narratives — humbled by forces (the Cube's uncontrollable growth, the slant, the carnivorous labyrinth) that escape their rational control.
- The Ninth Art
- The French designation for bande dessinée — sequential comic art elevated to the cultural status of fine art. The term situates comics alongside painting, sculpture, architecture, and film as a fully legitimate artistic discipline, the framework within which Schuiten has always operated and which contextualises his architectural rigour as genuinely serious practice.
- The Productive Page
- One of Peeters's "Four Conceptions of the Page" — a layout mode where the geometric arrangement of panels itself generates narrative meaning. A character descending a great staircase may inhabit progressively taller, narrower panels; the architecture of the page mirrors the architecture of the city.