Definition
Structured data is machine-readable markup added to web pages that explicitly labels content for search engines and AI systems — telling them not just what the page says but what the content means. The dominant vocabulary is Schema.org, typically implemented as JSON-LD embedded in the page's HTML head. For classic SEO, structured data triggers rich results (star ratings, FAQ accordions, how-to steps); for GEO, it serves a different purpose: it gives AI engines high-confidence facts to cite. An Organization block with @id, sameAs and foundingDate tells an AI engine that your brand is a verified entity, not just a keyword match. Structured data does not guarantee citation — engines still evaluate content quality and relevance — but it reduces the chance of misidentification or hallucination. Priority types for GEO are Organization (brand identity), Article (content authorship), FAQPage (question-answer pairs), HowTo (step-by-step instructions), and Product (specifications and reviews). Validate with Google's Rich Results Test and schema.org's validator before deploying.