Urbanĭtas—derived from the Latin urbanĭtas–ătis—originally described the cultivated condition of life in the city: an alignment between spatial form, civic conduct, and institutional order. Over time, the term has been reduced to a cultural or behavioural attribute, detached from the structural arrangements that sustained it. This notebook repositions urbanĭtas from a moral quality to a structural civic condition. It argues that urban coexistence depends on the deliberate articulation of legible scale, negotiable thresholds, and structural reciprocity between spatial and institutional systems. Contemporary urbanisation—characterised by functional segregation, infrastructural prioritisation, and governance fragmentation—has weakened this articulation, rendering coexistence an aspiration rather than a structured outcome. Urbanĭtas is reframed as a design and governance proposition. It occupies the relational in-between of form and institution, establishing a normative horizon for urban design: a position concerned with sustaining the spatial and institutional conditions under which civic reciprocity remains structurally possible, even under asymmetrical distributions of power. As the first conceptual node of the Research Notebook Series, this text grounds subsequent spatial and institutional explorations of urbanĭtas within a broader research architecture.