Authority is whether systems and people treat your property as a source. It is not a number a tool assigns you, and confusing the two has cost this industry a decade of clarity.
Third-party authority scores are link-graph estimates with a marketing name. They are genuinely useful for a fast first look at an unknown domain, and they are not evidence of anything, because they are modeling a thing they cannot see using inputs that are openly bought and sold. Quoting one as proof of authority is like quoting a credit score as proof of income.
What authority actually looks like
Being recognized as an entity
The most basic version: does anything understand that your property is a distinct thing with a subject, rather than a collection of pages? This is where declared structure earns its keep. A property that states what it is, what it covers, how its pieces relate, and what its vocabulary means is asking to be classified. One that leaves it to inference gets whatever inference produces.
The test is whether your brand name produces your property, and whether the subjects associated with that name are the ones you chose.
Being cited without being linked
Increasingly the important half. Being referenced in an AI answer, quoted in a forum, named in a comparison, mentioned in a talk. None of it produces a link, most of it produces no traffic, and all of it is evidence that something treats you as a source.
This is hard to measure and I will not pretend otherwise. What is measurable is the part in your own logs: whether retrieval-purpose crawlers come back to the same sections repeatedly, which is at least consistent with being used as a reference rather than indexed once and forgotten.
Being returned to
Repeat human visits and direct traffic are the oldest authority signal there is, and still the least gameable.
Specificity
Authority attaches to subjects, not to sites. A property with genuine depth on one narrow subject is treated as a source for that subject far sooner than a broad property with a page on everything. This is the part people resist, because narrowing feels like giving up reach.
How it gets built
Three things, none of them fast.
Consistency over time. Holding a position across years, and being able to point at when you started saying it, is evidence in a way that saying it louder never is. It also constrains what you should claim, because the value comes entirely from the claim still standing later.
Depth that survives inspection. Structure that impresses at a glance and falls apart when someone looks is worse than none, because it converts your best argument into evidence against you. If the glossary has 400 terms and 380 are one line of filler, the 20 real ones inherit the reputation of the filler.
Being specific enough to be wrong. A property that only publishes safe generalities cannot be a source for anything, because there is nothing in it anyone would need to cite. Specific claims, with dates and numbers and the occasional public correction, are what make a property quotable.
What is measured here
The authority signals lean on what can be observed rather than what can be estimated: brand-name query volume and its trend, direct traffic share, repeat crawler retrieval by section, referring domains earned rather than bought, and structural completeness of the entity declarations.
Deliberately excluded: any third-party composite authority score. Not because the tools are bad, but because a signal inventory that includes another vendor's model as an input inherits that model's assumptions without being able to inspect them.
The uncomfortable part
Authority is the slowest of the five dimensions and the one most resistant to effort. You can improve discovery in a week and commercial intent in a quarter. Authority moves on the scale of years, and the main thing that builds it is being useful about the same subject for long enough that stopping would be noticed.
Which is a genuinely annoying answer for anyone trying to increase a property's value before a sale, and it is the honest one. It is also why an established property with real authority sells at a premium that looks irrational until you try to reproduce it from scratch.