Housing is described as structures collectively; structures in which people are housed, living accomodation, dwelling units.
Housing unit means a house, an apartment, a mobile home or trailer, a group of rooms, or a single room occupied as separate living quarters, or if vacant, intended for occupancy as separate living quarters. Separate living quarters are those in which the occupants live separately from any other individuals in the building and which have direct access from outside the building or through a common hall. For vacant units, the criteria of separateness and direct access are applied to the intended occupants whenever possible.
See also:
"Housing" is in the NAICS Code "236115"