Schema

A schema is a shared, standardized vocabulary that tells machines what your content is, such as a "recipe," a "person," or a "price." Schema.org is the best-known of these vocabularies, jointly backed by the major search engines.

By adding schema markup to a page, you turn plain content into structured data, provides context that a machine can act on. That structured data is what powers rich search results, voice answers, and other features where a computer needs to work with meaning rather than just display words.