Full Definition
DefinedTerm schema is a type of structured data markup, implemented in JSON-LD, that identifies a webpage as the authoritative definition of a specific term. It is part of the Schema.org vocabulary and tells search engines and AI platforms with dedicated structured data pipelines: this page exists to define a concept, not just to mention it.
The markup includes three core properties: the term name, a concise description, and a reference to the DefinedTermSet it belongs to, typically a glossary or terminology hub. When implemented correctly, it creates a machine-readable signal that connects the term, its definition, and the organization maintaining that definition into a single, structured entity.
For AEO purposes, DefinedTerm schema has its clearest value inside Google's and Bing's own infrastructure, where dedicated systems process structured data for entity disambiguation and knowledge graph inclusion. For AI platforms that use flat-text retrieval, like ChatGPT, Claude, and Perplexity, the markup is read as plain text rather than parsed as structured data, so it does not function as a special trust signal the way the "structured data" narrative in this space often implies. What those platforms respond to is the visible definition itself: clear, direct, substantive, and self-contained. A 2025 Ahrefs study analyzing 1,885 pages across five major AI platforms found no meaningful citation uplift from JSON-LD schema on any platform tested, confirming that visible content carries more weight than markup for the platforms that matter most to B2B AEO. (Ahrefs, 2025)
DefinedTerm schema is most effective when paired with genuinely useful content. The markup signals intent to systems that can read it; the content earns the citation from all of them. A thin definition with perfect markup will not outperform a substantive definition with no markup. The combination of authoritative visible content and correct schema implementation is what positions a glossary page as a reliable AEO citation target, with each element doing a different job for a different part of the pipeline.
What are the three required properties for DefinedTerm schema?
The three core properties are name, which is the term being defined; description, which is a concise definition of the term; and inDefinedTermSet, which references the glossary or terminology hub the term belongs to. The inDefinedTermSet property is what connects an individual term to the broader collection it comes from, establishing the relationship between "AEO Readiness" and "AEO Glossary," for example. Without it, the term floats as an isolated definition with no organizational context. A fourth property, url, pointing to the canonical page for the definition, is strongly recommended even though it is technically optional, since it anchors the machine-readable entity to a specific, crawlable source.
Does DefinedTerm schema help a glossary page rank in traditional search?
Marginally and indirectly. DefinedTerm schema does not trigger a rich result in Google Search the way FAQPage schema used to, so there is no visible SERP feature associated with it. Its value in the Google ecosystem is at the entity level: helping Google's Knowledge Graph correctly categorize the page as a definitional source, which may improve how the page is characterized in AI Overviews and Gemini responses rather than in the organic link results. For traditional ranking purposes, the quality and depth of the visible definition content matters far more than the schema markup around it.
What is the difference between DefinedTerm schema and a simple meta description?
A meta description is a human-readable summary of a page, used by search engines to generate the snippet shown in search results. It communicates to humans what the page contains. DefinedTerm schema is a machine-readable declaration of what the page is: specifically, the authoritative definition of a named concept within a named collection. A meta description says "here is what this page is about." DefinedTerm schema says "this page is the definition of X, maintained by Y, and it belongs to glossary Z." The distinction matters for AI systems that process structured entity data separately from page content: the schema provides explicit classification that the meta description does not.