Hierarchical refers to a structure or organization that is arranged in levels, with each level being subordinate to the one above it. In such a system, there is an established order and authority flows from top to bottom, with decisions made at higher levels affecting those below. This type of arrangement can be seen in many different areas, including businesses, governments, and social groups. The word hierarchical comes from the Greek words "hieros" meaning sacred or holy, and "arkhos" meaning ruler or leader, so it suggests a sense of order and authority that is revered or respected.