A project management hierarchy is the hierarchy of roles in a project (based on leadership). By looking at the project management hierarchy, one can understand who reports to who and who has authority (implied or explicit) over who in the project.
For example, here's the project management hierarchy in an web project:
- Project Owner
- Project Sponsor
-- Project Manager
--- Team Leader
---- Database Architect
---- HTML Developer
In the above example, we understand that the HTML Developer reports to the team leader, who in turn reports to the project manager, and who finally reports to the project sponsor and the project owner.
There is no standard/generic project management hierarchy, but PM hierarchies for the same industry are very similar.