From OpenStreetMap Wiki
This key applies to ways only when, for instance, aerial views are not available. See landuse=* for areas.
|abutters||commercial||predominantly office buildings, business parks, etc.|
|abutters||industrial||predominantly workshops, factories, warehouses|
|abutters||mixed||where there is no clear predominance, for example mixed shops and residences in an inner city ring|
|abutters||residential||predominantly houses and apartments|
|abutters||user defined||All commonly used values according to Taginfo|