Over the last few decades, the notion of common has occupied an increasingly prominent place in the interdisciplinary debate as an alternative political horizon to neo-liberal dynamics and in turn as an envision of new social engagement also in the domain of urban transformations. To a larger extent, commoning pushes further such discourse because this verb condenses the social practice used by commoners in the course of managing resources and reclaiming the construction and maintenance of the commons. The recent typological innovations produce a multiplication of the meanings from the common declination and a particularly abundant associated vocabulary: co-housing, cluster, common space, apartment-sharing, participatory project, etc. Among these terms, several address the question of the scale of pooling, referring in history to notions already absorbed by architectural culture. In such framework, the paper aim to reconsider the notion of neighborhood unit, pioneered by Clarence Perry in 1929, but also most influential planning idea for a long time, through recent Elinor Ostrom's theories on collective and the perspective of the commons. Beyond the conception of neighborhood as integral unit for planning, the economical unit for construction and administration, and the social unit for living, the paper proposes to question legacy and current relevance as architectural tool actualised in several today housing projects. Its religious precedents, security arguments, past and prospective political significance will be discussed in the light of contemporary debate on the common. The critical re-reading of significant architectural experiences from French workers' housing settlements and communities in the Swedish folkhemmet context till Swiss housing cooperative groups aims to assign concrete benchmarks to this delineation of ideas and spatial conceptions under different times and conditions. The investigation accomplishes to highlight the paradigm shift induced by the dynamics around the commons, in a temporal and speculative leap between the modern housing administration and its possible emancipation in an expanding operational horizon.