/terms/defined-term-schema · 4 min read · intermediate

DefinedTerm schema

DefinedTerm is a schema.org type representing a term defined elsewhere (typically in a glossary), helping systems that parse structured data understand a term, its definition, and its relationship to a glossary source.

Citation status

ChatGPT·Perplexity·Claude0×Copilot0×Gemini0×

Last checked 2026-06-16

What is DefinedTerm schema?

DefinedTerm is part of schema.org's core vocabulary1, formalizing the structure of a defined term. DefinedTerm payloads commonly include: name (the term itself), description (the definition text), optional alternateName (synonyms), inDefinedTermSet (the glossary or terminology resource it belongs to), and canonical url. Schema.org does not strictly require any of these: name and description are universally present in practice; inDefinedTermSet is critical for glossary-collection semantics. Practitioners commonly observe that DefinedTerm-structured definitions are easier for AI engines to extract verbatim than equivalent prose-only definitions; whether the independent effect comes from the markup itself or from the underlying definition-headed structure has not been isolated by public study.

A minimal valid DefinedTerm JSON-LD looks like this:

{
  "@context": "https://schema.org",
  "@type": "DefinedTerm",
  "@id": "https://example.com/glossary/example-term",
  "name": "Example Term",
  "description": "A concise definition of the term.",
  "url": "https://example.com/glossary/example-term",
  "inDefinedTermSet": {
    "@type": "DefinedTermSet",
    "@id": "https://example.com/glossary",
    "name": "Example Glossary",
    "url": "https://example.com/glossary"
  }
}

Embed this inside a <script type="application/ld+json"> tag in the page's <head>. Google's Structured Data guidelines2 document the broader pattern. The same shape works in retrieval flows that parse JSON-LD; Perplexity, Claude, and ChatGPT have observable behavior consistent with parsing DefinedTerm markup when present, though specific parsing details are not vendor-documented for any of those engines.

Status in 2026

Increasingly central in glossary and documentation-site GEO workflows. The DefinedTerm type was added to schema.org's vocabulary in November 2019 (schema.org v5.0) and gained widespread adoption in 2025-2026 as practitioners reported increased citation visibility for schema-backed glossaries in ChatGPT, Perplexity, and AI Overview. Whether engines explicitly favor schema-tagged definitions over equivalent prose-only ones, or whether the observed visibility comes from correlated signals (glossary structure, definition-headed prose, citation patterns), has not been isolated by public study.

A worthwhile counterweight: schema is the label on the bottle, not the wine. Jono Alderson (independent technical SEO consultant, widely respected on structured data) framed the limit honestly in a November 2024 piece on his blog: "Maybe Schema.org is 'just' labels and connections. Maybe we don't get any magic powers from it right now. Maybe we were over-sold by Google."3 DefinedTerm and FAQPage help engines parse a page that already deserves citation. They don't make a low-authority, thin, or stale page worth citing. Ship schema as one signal among many (authority, freshness, source quality), not as a magic switch.

Note on this entry's territory (paired with the FAQ schema and JSON-LD entries as components of the schema cluster): DefinedTerm as a schema.org type is vendor-canonical. Schema.org maintains the vocabulary, Google Search Central documents its use in structured data, JSON-LD provides the syntax envelope. The application to specific commercial AI search engines (whether Perplexity, ChatGPT, Claude actually weight DefinedTerm over prose definitions in retrieval and citation) is non-vendor-canonical because engines do not publish their structured-data weighting. The content-side application (using schema as one signal alongside authority, freshness, and source quality, rather than as a citation magic switch, as Jono Alderson's quote above frames) sits in practitioner-discipline territory: writers can directly verify schema validity via the two validators below. Paired with FAQ schema (Q&A structure with its May 7 2026 deprecation context) and JSON-LD (the syntax envelope all schema types share), DefinedTerm covers the term-definition structure, the foundational schema-class for glossary content.

How to apply

DefinedTerm is the primary schema type for glossary content, and increasingly useful for any page that defines an industry concept. Three concrete moves:

  • Generate the JSON-LD server-side from frontmatter: don't hand-author it per page. Build a small helper that takes { name, description, inDefinedTermSet } and emits a valid DefinedTerm payload, then inject it into the <head> via your framework's metadata API (Next.js, Astro, SvelteKit all support this).
  • Wire inDefinedTermSet to a stable glossary URL: this is how the markup expresses that term X belongs to glossary Y as a collection. Without inDefinedTermSet, each term looks like an isolated definition; with it, the markup expresses a defined-term collection. Whether engines build or use a subgraph from that relationship is not publicly documented.
  • Validate every payload before deploy: paste the rendered JSON-LD into Schema.org's validator and Google's Rich Results Tester. DefinedTerm has very few expected properties (name plus a description in practice), so most validation issues are typos in property names.

What to skip: marking up product names or company names as DefinedTerm. They're better served by Organization or Product schema. DefinedTerm is for concepts, jargon, and terminology.

How it relates to other concepts

  • Sibling to other schema.org types: FAQPage, HowTo, Article.
  • A useful schema layer for glossary-style GEO content strategies. The current cluster framing favors visible content first, with schema as machine-readability hygiene, rather than schema-first content strategies (which over-rely on markup as a citation-rate multiplier).
  • Often paired with inDefinedTermSet (a DefinedTermSet entity) to provide collection-level metadata that may help systems understand term-glossary relationships; the role of DefinedTermSet in vendor authority evaluation is not publicly documented.
  • Commonly hypothesized to support cite-ability by structuring the claim into a discrete machine-readable unit; the independent effect relative to a well-written prose definition has not been isolated by controlled study.

Footnotes

  1. Schema.org DefinedTerm vocabulary specification: schema.org/DefinedTerm. ↩

  2. Google Search Central structured-data guidelines (intro): developers.google.com/search/docs/appearance/structured-data/intro-structured-data. ↩

  3. Jono Alderson, "What if Schema.org is just… Labels?" jonoalderson.com, 2024-11-03. jonoalderson.com/conjecture/what-if-schema-org-is-just-labels. ↩

Part of Schema cluster· editorial cluster, not a semantic link

Also in this cluster: Article Schema · BreadcrumbList Schema · FAQ Schema · HowTo Schema · JSON-LD

Related terms

Mentioned in· auto-generated from other terms' related lists

FAQ

How do I add DefinedTerm to my page?
Embed JSON-LD in the page's <head> with @type: DefinedTerm and the core properties: name (the term), description (the definition), url (the canonical URL), and inDefinedTermSet (the glossary it belongs to). Optional: alternateName for synonyms, datePublished, dateModified.
Does DefinedTerm replace FAQ schema?
No; they complement. DefinedTerm marks the term itself as a structured entity; FAQPage marks questions and answers about the term. A glossary page typically ships both.
Does Google's AI Overview parse DefinedTerm?
Yes, the markup is parseable. Whether DefinedTerm-tagged definitions are cited at higher rates than equivalent prose-only definitions has not been isolated by controlled study; practitioners report seeing DefinedTerm-marked pages cited frequently, but the comparison against well-structured prose definitions (same content, no schema) is not measured. Ship it as low-cost machine-readability hygiene, not as a confirmed citation-rate multiplier.

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