Schema.org
The shared vocabulary of structured data types, Product, Organization, FAQPage, Review, maintained jointly by Google, Microsoft, Yahoo, and Yandex, that powers structured data markup.
What it means
Schema.org defines the actual vocabulary used when a site adds structured data: what properties a Product type can have, how a Person relates to an Organization, what a valid AggregateRating looks like. It's not a single company's format, it's a shared, versioned standard that search engines and increasingly AI crawlers all parse the same way. Using schema.org types correctly, rather than inventing custom properties or misusing existing ones, is what makes structured data actually machine-readable instead of just technically present.
Why it matters for Shopify
Shopify merchants implementing structured data should follow schema.org's defined types and properties precisely, incorrect or invented properties get ignored by the platforms structured data is meant to inform.