Topical Authority
Topical authority describes how comprehensively and consistently a website covers a particular subject area, which search engines and AI systems use as a signal of subject expertise. The more completely and coherently a topic is covered, the more likely Google is to treat the website as a credible source in that field.
In practice
Topical authority is built through content clusters: a central pillar page on a main topic, supported by several in-depth sub-articles that are sensibly linked to one another. What matters is sustained depth of content over a longer period rather than isolated one-off articles with no thematic connection. The principle is relevant to both classic SEO and GEO (Generative Engine Optimization), because AI-driven answer systems prefer to cite sources that demonstrably cover a topic in depth.