위계가 · 위계를
hierarchy, rank order
Example
그 회사는 위계 질서가 매우 엄격해요.
That company has a very strict hierarchy.
Word parts
위 rank+계 steps
Literally 'rank and steps' — positions stacked like stairs.
Good to know
Homonym: 위계(僞計) means 'deceptive scheme', as in the legal term 위계에 의한 업무방해.