A content cluster is an editorial organization strategy in which a pillar article (broad and in-depth) is connected to several satellite articles (specific and focused) through internal links. The idea is that the set as a whole demonstrates topical authority both to search engines and to generative AIs.
For example: a pillar on "Response Marketing" can have satellites such as "What is GEO?", "How link building works", "What are Core Web Vitals" and "How to measure SEO ROI". Each satellite links back to the pillar and to the others, creating an interconnected content network.
For GEO, clusters are especially powerful because they mirror the way AIs process information via query fan-out. When the AI breaks a complex question down into sub-questions, your satellite articles can answer each sub-question individually, increasing the chance of citation in the synthesized answer.