What was an Aztec commoner housing and landholding unit called?

An Aztec commoner housing and landholding unit was called a calpulli.

The Classical Nahuatl term calpulli referred to an organized community within a larger Nahua city-state, or altepetl. Its members lived together, coordinated access to land, shared responsibilities, and carried out religious and administrative duties. Calpulli could be based on kinship, shared ethnic identity, occupation, or residence, so they were not simply nuclear or extended families.

A calpulli helped organize agricultural production, including the use of fields, chinampas, and terrace systems. It also helped collect tribute, often in goods or labor, and could provide military organization. Neighborhood schools called telpochcalli were associated with these districts, giving young men training for community work and warfare.

Readers sometimes confuse calpulli with altepetl. The altepetl was the larger city-state or polity, while a calpulli was one of its constituent communities or wards. Spanish colonial sources sometimes described calpulli as barrios or parcialidades, but those labels only approximate their social, economic, and political roles.