The introduction and gradual construction of the notion of “habitat” within architectural discourse after World War II reflectsa process of incremental enrichment of a meaning, of a concept highlighting deep changes and new trajectories in the epistemology of architecture and urban planning. A first appearance of “habitat”took place in postwar CIAM, to declaredly move the reflection form the domain of the “machine à habiter” towards a dimension of “human scale”; still, no agreement is found, mostly for reasons of language, on a definition of habitat to be commonly accepted; the envisioned Charter of Habitat, intended to substitute the Athens Charter, remains unwritten; an exclusively Euro/North-Atlantic cultural dimension of architectural debate comes out as anachronistic, as “habitat” evolved from an urban and architectural notion towards one embedded within the broader domain of human rights. These trajectories spring directly from the unresolved definition of “habitat,” a legacyof the dissolving of CIAM throughout the 1950s.