Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Object Groupings and Systems (hierarchy name)
4. object groupings
5. [object groupings by specific context]
6. environments (object groupings)

Anotations

Scope note:

Environments located below ground level, including those within structures. For the structures themselves, if intentionally built below ground level, use "underground structures." To describe objects that are or have been in the ground and covered with earth, use "buried."