SEO silo
An SEO silo is a way of grouping a site's pages by topic, with internal links that mostly stay inside each group.
An SEO silo is a way of organizing a website into separate topic sections, where the pages in each section link mostly to each other and to one main page for that topic. The idea is to make it obvious, to people and to search engines, which pages belong together and which page is the best one on each subject.
It's useful when a site has grown messy. Clear sections make it easier to see where a new page belongs, and what's missing.
How a silo is built
You pick your main topics and give each one a hub page. The pages under it cover parts of that topic and link back up to the hub and across to their neighbours. The web address often follows the same shape, with each section in its own folder.
For example, Fernhill Coffee might have three silos: brewing, beans and subscriptions. The brewing hub links to guides on French press, pour-over and espresso. Each guide links back to the hub and to the other guides, and to the beans section only where it genuinely helps the reader pick a coffee.
Strict silos and why they've softened
Early silo advice said never to link between sections, so that each silo kept its strength to itself. That's mostly gone. Links between sections are fine when a reader would want to follow them, and blocking them only makes the site harder to use. Today most people describe the same idea as topic clusters.
Why it helps in AI search
A clear structure helps any bot work out what your site covers and which page is the main one on a topic. When an AI platform searches for a subject, a well-linked hub with focused pages under it gives it a page that covers the whole question, and others that cover each part. Pages that sit outside any section, with no links pointing in, are easy to miss.