Hierarchy classification:

1. top of the aat hierarchies
2. Physical Attributes Facet
3. Attributes and Properties (hierarchy name)
4. [attributes and properties by specific type]
5. positional attributes
6. [positional attributes by context]

Anotations

Scope note:

Describes objects that are or have been in the ground and covered with, often in direct contact with, earth. For structures intentionally built below the earth's surface, use "underground structures." With regard to the effects of being buried, use "underground environments."