Schema.org

The vocabulary is organized into a hierarchy of types, each with associated properties. The root type is Thing, from which more specific types like CreativeWork, Event, Organization, Person, and Place inherit. This inheritance model means a LocalBusiness inherits properties from both Organization and Place, allowing for rich, layered entity descriptions without redundant markup.

Schema.org defines the vocabulary, not the syntax. It can be expressed in three formats recognized by search engines:

• JSON-LD: The recommended format, embedded in a <script> tag as a standalone data block.
• Microdata: HTML attributes woven directly into existing page content.
• RDFa: An attribute-based syntax for embedding rich metadata within HTML. JSON-LD is preferred by Google for its ease of implementation and separation from the visual DOM.

Schema.org markup is fundamentally about describing entities—the real-world things a page is about—not just keywords. By using properties like @id and sameAs, you explicitly link your described entity to canonical URIs in external knowledge bases like Wikidata or Wikipedia. This practice, known as entity reconciliation, helps search engines disambiguate your entity and consolidate authority signals into a unified Knowledge Graph node.

The primary incentive for implementing Schema.org is to qualify for rich results—visually enhanced search listings. Specific types and property combinations trigger these features:

• FAQPage enables an accordion-style Q&A display.
• HowTo shows step-by-step instructions with images.
• Product + AggregateRating + Offer triggers star ratings and price displays.
• JobPosting enables inclusion in Google's dedicated job search experience. Search engines use these structured signals to move beyond the blue link.

While the core vocabulary covers broad use cases, Schema.org provides an extension mechanism for specialized domains. Hosted extensions (e.g., for Bib extension for bibliographic data, or Auto extension for vehicles) are reviewed and approved by the Schema.org steering group. External extensions can be created by any community for their own purposes, allowing domain-specific vocabularies to build upon the core hierarchy without forking the standard.

The process of aligning a local entity to a canonical URI in an external authority hub. The sameAs property is the primary mechanism for explicit disambiguation. By linking an Organization node to its Wikidata Q-ID, Wikipedia URL, or Google Knowledge Graph ID, you collapse multiple textual mentions into a single, deterministic node. This consolidation prevents entity fragmentation and strengthens the confidence score search engines assign to your brand's knowledge panel.

A high-priority property that explicitly signals the primary subject of a webpage. When a page contains supplementary content (sidebars, footers, related posts), mainEntity cuts through the noise to declare the semantic core. For an article page, mainEntity points to the Article object; for a product page, it points to the Product. This sharp signal is critical for entity extraction algorithms attempting to index the definitive topic of a URL.

A property that identifies sections of text optimized for text-to-speech (TTS) conversion. Using CSS selectors or XPath, speakable highlights the concise, digestible summary a voice assistant should read aloud, bypassing verbose legal disclaimers or complex tables. This allows publishers to control the audio UX of their content on Google Assistant, ensuring the spoken answer is a natural, high-quality summary rather than a raw scrape of the first paragraph.

A type used within a DefinedTermSet to formally define a word or phrase. This markup allows search engines to extract exact definitions for display in dictionary-style features. The termCode property links to an external controlled vocabulary, while description provides the human-readable definition. Implementing this for technical glossaries helps establish topical authority by explicitly mapping internal jargon to standardized industry definitions.