definition
strict definition
boundary
The outline of a region or the footprint of a structure, stored as a polygon of geographic coordinates.
A boundary is the outline of something on the map, held as a polygon of coordinates. For a region it is the administrative border, for a structure the footprint the building covers.
It is drawn, not calculated. A pinpoint location is a single point and can be derived from a boundary, but no boundary can be recovered from a pinpoint.
A region without a boundary is still a region. Many places are recorded with a name, a register code and a center while no polygon has been imported yet, and that gap says nothing about the place itself.