If something is hierarchical it has clear levels of power and importance, such as a hierarchical corporation that has the boss at the top, or the hierarchical social order of junior high school popularity.
It's lonely at the top. That pretty much sums up hierarchical, pronounced "high-eh-RAR-ki-cal." In a hierarchical structure, people or groups are arranged according to ability or status. It helps to think of a triangle, with the leader at the highest point, layers of managers under him or her, and at the base, or widest part, the masses of workers who make up the largest part of the organization.