a series of ordered groupings of people or things within a system
"put honesty first in her hierarchy of values"
the organization of people at different ranks in an administrative body
"The new manager spent her first week studying the company's hierarchy to understand who reported to whom."
A body of authoritative officials organized in nested ranks.
"The new military hierarchy was established to ensure clear command from general officers down to enlisted soldiers."
In plain English: A hierarchy is an organized system where people, groups, or things are ranked from most important to least important.
"The company's hierarchy places the CEO at the top with managers and employees reporting below them."
Usage: Use hierarchy to describe any system where groups or individuals are arranged in levels based on authority, such as corporate structures or military chains of command. It is often confused with "stratification," but while stratification refers broadly to layers within a society, hierarchy specifically implies a structured order of power and rank.
The word hierarchy comes from Ancient Greek, where it originally meant "the rule of a high priest." It entered English through Middle English and Old French, with the spelling adjusted around 1500 to match its Latin roots more closely.