What is topical authority?
Topical authority is the depth and consistency of a site’s coverage of a subject, so it can answer the cluster of questions a buyer asks, not a single keyword. It is a description of a body of work. Engines do not publish a topical authority score you can optimize against.
Why it matters for AI visibility
AI answers rarely stop at one query. Fan-out and follow-ups pull in pricing, implementation, alternatives, and failures. A site that has explained the cluster in specific, internally linked pages gives a retriever more relevant passages to choose from. That is why topical authority matters for AI visibility. It is earned by coverage that a practitioner would recognize as complete, not by publishing dozens of near-duplicate definitions. Each page should own a question, link to the neighbors, and avoid contradicting them. Authority is also external: other credible sites describe you in that category. You infer progress by watching citations across the prompt cluster over time. You do not infer it from a third-party “authority” number that was built for classic links and then relabeled. If one prompt is cited and the adjacent prompts never are, the cluster is unfinished, whatever a score says.
Example
A security vendor has a single page targeting “best practice.” Buyer prompts also ask about rollout time, audit logs, and how it differs from a named rival. Adding those answers as separate, linked pages is topical coverage. Whether citation frequency rises is a later measurement, not a property of the word count.
Related terms
Query fan-out is how one question exposes the missing parts of the cluster. Entity SEO makes the brand behind the cluster unambiguous. E-E-A-T is whether the coverage shows real experience. Authority without those is just volume.