Authority source
n.Origin
From Latin auctoritas (legitimacy, credit). In SEO and information architecture, refers to any entity recognised as a reliable reference on a subject by search engines and LLMs.
Definition
A domain, page or author that search engines and language models cite spontaneously when asked about a subject. Authority is not a property you assign yourself: it is a position others grant you, and it is observed from the outside.
It is built through coherent accumulation rather than volume. Three materials compose it. Semantic coherence first: a body of content that answers itself, cites itself and covers a field without self-contradiction — a cluster, not a pile of unrelated articles. Depth next: on a given subject, going further than the page that merely defines, down to edge cases, counter-examples and what does not work. Verifiability last: traceable claims, sourced figures, examples the reader can replay.
These three overlap with what Google calls E-E-A-T — experience, expertise, authoritativeness, trustworthiness. One clarification matters, because the confusion is common: E-E-A-T is not a ranking factor the algorithm measures directly. It is an evaluation framework, described in the guidelines given to the human raters who assess result quality, and it informs how ranking systems are trained. You do not optimise it like a tag; you embody it, or you do not.
Authority is also lost, faster than it is won: one false definition left online, one stale figure, one contradiction between two pages of the same site is enough for another source to be preferred. Which is why editorial review of a reference corpus is not maintenance but foundational work — a lexicon that is wrong about its own vocabulary is authoritative about nothing.
Example
"If in 6 months a journalist searching 'headless e-commerce France' does not land on me first, we haven't built the authority source yet — regardless of how many articles have been published."