boundary stone
noun1
A stone marker, in use since ancient times, set to indicate the limits of property, jurisdiction, or territory, bearing inscriptions or symbols identifying the authority that placed it and that protected the region.
- The boundary stones are of interest here because they were decorated with symbols of the gods, most of which correspond to planets or constellations.1998, John H. Roger, “Origins of the ancient constellations: I. The Mesopotamian traditions”, in Journal of the British Astronomy Association, volume 108, number 1, page 11, column 2: