DefinedTerm Schema for Glossaries

#01What do the two types mean?

Sources: schema.org DefinedTerm, schema.org DefinedTermSet. schema.org's guidance: use name for the term, termCode for an alphanumeric code, description for the definition, and about for what the term is about.

#02Does Google support it?

DefinedTerm doesn't appear in Google's structured data search gallery, the list of markup that can produce Google rich results (Google). So you won't see a "glossary" rich result. Our view: the markup is still worth adding when it's cheap to generate from your CMS, because it states unambiguously which term a page defines and which glossary it belongs to. Don't expect a measurable ranking or citation lift from it alone; we're not aware of published evidence either way.

#03How do you build it step by step?

1. Create the set on the glossary index page, with a stable @id.
2. Give each term a page (or an anchor) with a stable URL.
3. Mark up each term with name, description and inDefinedTermSet pointing to the set's @id.
4. Keep the definition visible. The description should match the first sentence or definition on the page (Google).
5. Validate in the Schema Markup Validator.

Expected result: the validator shows a DefinedTerm with a name, description and a DefinedTermSet reference, with no errors.

#04What does the JSON-LD look like?

Glossary index page (fictional):

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "DefinedTermSet",
  "@id": "https://www.example.com/glossary/#set",
  "name": "Example GEO Glossary",
  "url": "https://www.example.com/glossary/"
}
</script>

Single term page (fictional):

<script type="application/ld+json">
{
  "@context": "https://schema.org",
  "@type": "DefinedTerm",
  "@id": "https://www.example.com/glossary/llms-txt#term",
  "name": "llms.txt",
  "description": "A proposed Markdown file at a site's root that gives language models a curated overview of the site and links to key content.",
  "url": "https://www.example.com/glossary/llms-txt",
  "inDefinedTermSet": "https://www.example.com/glossary/#set"
}
</script>

On a long single-page glossary, list terms in the set's hasDefinedTerm array instead.

#05Should you combine it with other types?

Our view: a glossary entry page is also an article. You can keep your normal Article or WebPage markup with author and dates, and add the DefinedTerm as the page's mainEntity. That keeps authorship (see Article author schema) while stating which term the page defines.

#06What goes wrong? (Troubleshooting)

#07Why does this help AI answers?

Our view: AI tools answering "what is X" look for a concise, quotable definition. A page whose first sentence defines the term, whose markup repeats it and whose glossary links related terms is easy to parse and quote. The markup is one small signal; the clear definition on the page does most of the work. See our glossary entry on schema markup.

#08How should glossary definitions be written?

Our view: write the definition so it stands alone. Start with the term, say what category it belongs to, then what distinguishes it, in one or two sentences. Avoid starting with "In this article". Then expand with an example, related terms and sources. Keep the description to that standalone definition rather than the whole entry, and update both together when the meaning shifts.

#09Exercise

#10How do you maintain it over time?

Our view: treat the glossary like a product. Assign an owner, review definitions on a fixed schedule (for example every 90 days) and log changes with a visible "last reviewed" date. When you retire a term, redirect its page to the closest live term rather than leaving a dead DefinedTerm behind. When you add a term, link it from at least two related entries so it doesn't become an orphan. Re-validate the markup after any template change.

#11Checklist

• DefinedTermSet with a stable @id
• One DefinedTerm per term page
• name, description, inDefinedTermSet
• description matches the visible definition
• Validated in the Schema Markup Validator

#12From MentionX data: which pages engines citeOriginal data

Method. Read-only aggregate queries over MentionX scans from 22 August to 29 October 2026 (UTC): 2,217 engine runs (2,154 completed) across 18 anonymised projects and six engines.

Glossary pages are usually published as articles or docs. In the MentionX sample, articles are the largest cited type and docs a smaller one:

Problem prompts, which often start with "what is", mention brands least often:

Our view: definitions answer problem and "what is" prompts, where engines rarely name a brand but still cite sources. A clear glossary can earn those citations.

Limits. A convenience sample of mostly B2B software projects, run through engine APIs, which can behave differently from the consumer apps. Perplexity, Copilot and DeepSeek figures come from a single day (26 October 2026), so treat them as a snapshot, not a trend.

#13Worked example: Ledgerline marks up its accounts-payable glossary

Ledgerline is a fictional accounts-payable tool. Figures are illustrative.

Ledgerline has a glossary of 60 accounts-payable terms on separate pages. Many definitions start with background rather than an answer.

The content team rewrites each definition so the first sentence says what the term means, followed by an example and a link to a related guide. It adds a DefinedTermSet on the glossary index page and a DefinedTerm on each term page with the name, description and a link to the set.

It tests the markup in the Schema Markup Validator and adds a review step for terms affected by regulatory changes.

#14Should each term have its own page?

Our view: for important terms, yes, because a dedicated page can answer the question fully and be linked from other content. For minor terms, a single glossary page with anchors is enough. Either way, each definition should be visible text.

#15How do you choose which terms to include?

List the terms your audience searches for and asks about, from sales calls, support tickets and prompt checks. Include terms specific to your product only where customers need them. Avoid padding the glossary with terms you can't explain well.

#16How do you link glossary terms?

Link from guides and articles to the glossary entry the first time a term appears. Link from each glossary entry to the guide that covers the topic in depth. These links help readers and engines connect definitions to fuller explanations.

#17How should you handle terms with several meanings?

State each meaning separately, with the context in which it applies. Say which meaning your product uses. Don't merge different meanings into one vague definition.

#18How do you write definitions for a general reader?

Use plain words, and avoid defining a term with other jargon. Give an example from a real situation. Say what the term isn't, if it's often confused with something else. Our view: a definition that a new hire could understand on their first day will also work in an AI answer.

#19How do you structure a glossary page?

Give each term a heading with the term itself, followed by the definition. Add synonyms and abbreviations in the first sentence. Link to related terms and guides. On the index page, list terms alphabetically with short definitions and links.

#20How do you mark up a term page?

Use DefinedTerm with the name, a description that matches the visible definition and inDefinedTermSet pointing to the glossary. Add a termCode if you use one. Keep the description short and identical to the visible first sentence where possible.

#21How do you measure glossary impact?

Run "what is" prompts for your terms and check whether engines cite your glossary. Track search traffic to glossary pages, and see which terms lead readers on to guides and product pages.

#22How do you avoid thin glossary pages?

Don't create pages with a single sentence and nothing else. Add an example, context and links so each page is useful. Merge minor terms into a single page.

#23How do you handle product-specific terms?

Define terms that are specific to your product in your docs or glossary, and say clearly that they're product terms. Link them to the relevant feature page. Avoid giving product terms the same names as general industry terms, which can confuse readers and engines.

#24How do you keep definitions consistent?

Use the same definition wherever a term is defined on your site, and link to the glossary instead of redefining terms in each article. Review the glossary when product or industry terms change. Our view: conflicting definitions on the same site are a common source of wrong AI answers.

#25How do you add new terms?

Add terms as they come up in support, sales and content. Give each new term an owner who checks it before publishing.

#26How do you get glossary entries cited?

Make the first sentence a complete, accurate definition. Add a short example and a source where the term comes from a standard or regulation. Link to the entry from your guides. Check "what is" prompts for your main terms every few months and improve entries that aren't cited. Our view: the clearest definition on the web is often the one engines quote. Track which entries readers visit most and review those first, since they're the ones most likely to be quoted elsewhere.

#27Common questions

Does Google support DefinedTerm? It's valid schema.org, but Google doesn't use it for a rich result.

Is the markup worth adding? Our view: it's low effort if your glossary is templated, but clear visible definitions matter more.

How long should a definition be? Our view: one sentence for the answer, then a short paragraph with an example.

#28Related

• Schema markup for AI search
• Dataset schema for research pages