Short and sweet:
Schema markup; a specific vocabulary of structured data, maintained through Schema.org, used to label webpage content in a format search engines and AI systems universally recognize.
The most common technical method for implementing structured data on a website.
See also: Structured Data, SEO, AEO
Schema markup is essentially the shared dictionary that makes structured data work: rather than every website inventing its own way to label a product price or an author name, Schema.org provides a standardized set of terms that search engines from Google to Bing, and increasingly AI models, all agree to recognize. It’s typically added to a page’s code using a format called JSON-LD, which sits invisibly in the background without changing how a page looks to a human visitor. Getting it right doesn’t guarantee a rich result or an AI citation, but getting it wrong, or leaving it out entirely, makes both considerably less likely.
A developer might add JSON-LD schema markup to a services page, explicitly labeling the business name, service type, and service area.
A local business could use schema markup to tag its hours, address, and phone number, increasing its odds of a rich local search result.
A glossary site might apply DefinedTerm schema markup to each entry so search engines and AI tools recognize the page as a definition rather than a generic article.
