SHAPE_Area is a system field in a geodatabase polygon feature class that holds the geometric property 'area' for a shape. For the general concept of area, use the area tag.
Note this tag applies specifically to the system attribute field for area. For questions related to the general concept of the area of a shape, use area.
SHAPE_Area is a system field in a geodatabase polygon feature class that holds the geometric property 'area' for a shape. This value is in the units of the data's coordinate system, and is updated whenever the geometry is edited.
Note that this is a system created field. The values and units cannot be modified manually. It is possible to create a field with this name, but it will not be recognized as the system field or updated which happens only in a geodatabase. This is a common error when a feature class is exported to a shapefile. At that point, the field is no longer a system field and will not be updated if the geometry is changed.
It is also possible to end up with multiple area related fields, some of them named SHAPE_Area or variations thereof, through joins, geoprocessing operations such as Union, and numerous other import/export methods. However there is only one true system area field that will automatically update with geometry changes - all other fields must be 'manually' updated or recalculated.