In Plain English
Structured data gives eligible systems an explicit, machine-readable description of certain visible content. It commonly uses the Schema.org vocabulary, and JSON-LD is a widely used format. The markup must agree with what a visitor can actually see; it should not invent reviews, prices or other facts. Correct markup can improve interpretation and may establish eligibility for particular search features, but the system still decides whether and how to use it.
Why it matters
Accurate structured data removes some ambiguity about supported content types. It can help systems connect properties such as a term and its definition, while keeping the visible page as the source of truth.
Choose markup only when the page contains a supported type and the properties can be maintained accurately. Validate syntax during development, then check the rendered page rather than only the template. A technically valid block can still be misleading or ineligible when required visible information is absent. Structured data is an additional description of the page, not a replacement for clear headings, accessible content, useful internal links or normal metadata.
Example
{"@context":"https://schema.org","@type":"DefinedTerm","name":"Indexing"}This conceptual JSON-LD describes only the visible term; it does not invent business details.
Common misunderstanding
Schema markup is not a secret visibility switch. It guarantees neither rich results, rankings nor AI citations.