A hierarchy is a collection of entities that are related and managed as a group. Those entities include permanent objects (the hierarchy handles), primary objects at the root of a tree, and other objects such as keys in the tree. NV indexes belong to a hierarchy but aren’t in a tree. Entities, other than permanent entities, can be erased as a group.
The cryptographic root of each hierarchy is a seed: a large random number that the TPM generates and never exposes outside its secure boundary. The TPM uses the seed to create primary objects such as storage root keys. Those keys form the parent at the top of a hierarchy and ...