Hierarchy is polyamory's ranking system: a "primary" partner gets more time, commitment and decision-making power than a "secondary" one — whether by explicit rule or just by how life shook out.
Two different things get bundled into the word. One is entanglement: the "primary" is the person you share a mortgage, a calendar and maybe kids with; the "secondary" has their own place, their own life, and a smaller slice of yours. The other is power — who gets a say over whom. Those two don't have to travel together, and the whole modern argument about hierarchy is basically about prying them apart.
That's the prescriptive-versus-descriptive line educators keep drawing. Descriptive hierarchy is just honesty about your calendar: one relationship is more built-in than another and nobody's hiding it. Prescriptive hierarchy is rules — curfews, vetoes, a ceiling set in advance that says a secondary can never become anything more, no matter what grows between you. The first describes where you are today; the second dictates where anyone is allowed to end up. Most of the fights people have about "hierarchy" are really about the second one wearing the first one's clothes.
And "secondary" is a label a lot of people flatly refuse to wear — being told your relationship is structurally capped feels less like a description and more like a verdict. There's data in the mix too: the one big empirical study found people report more commitment and more outside acceptance with primaries, but more secrecy — and, plot twist, a bigger share of their time spent on sex — with secondaries. Ranking humans by tier is, as one educator puts it, a "pretty capitalist, commodifying way to look at" love. The vocabulary isn't the villain. Using it to make someone disposable is.