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: 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 matters because AI platforms increasingly use structured data as a trust signal when selecting sources to cite. A page with DefinedTerm schema is easier for an AI to identify as a definitional source than a page that simply contains the word somewhere in its body copy. The markup does not guarantee inclusion, but it removes ambiguity about what the page is and what it defines.
DefinedTerm schema is most effective when paired with genuinely useful content. The markup signals intent; the content earns the citation. A thin definition with perfect markup will not outperform a substantive definition with no markup. The combination of authoritative content and correct schema implementation is what positions a glossary page as a reliable AEO citation target.