> For the complete documentation index, see [llms.txt](https://iea-task-43.gitbook.io/iea-task-43-glossary/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://iea-task-43.gitbook.io/iea-task-43-glossary/terms/syntax.md).
# Syntax
A set of rules that defines the combinations of symbols that are considered to be correctly structured statements or expressions in a language or data format. Syntax therefore refers to the form of the data or code, and is contrasted with [semantics](https://github.com/IEA-Task-43/glossary/blob/main/terms/collections.md) – the meaning.
## Examples
We can express semantically identical data (in this case metadata for a webpage header) using different syntaxes.
{% tabs %}
{% tab title="HTML" %}
In HTML (HyperText Markup Language) with opengraph attributes:
```html
```
{% endtab %}
{% tab title="JSON" %}
In JSON (JavaScript Object Notation):
```json
{
"type": "article",
"description": "Science to build on",
}
```
{% endtab %}
{% endtabs %}
## Useful syntaxes for metadata
We think the following syntaxes will be useful for definition of [metadata](https://github.com/IEA-Task-43/glossary/blob/main/terms/live-edit-and-locked-edits.md) (but this is by no means an exhaustive list:
* [OWL (Web Ontology Language)](https://www.w3.org/TR/owl-semantics/syntax.html)
* [JSON (Javascript Object Notation)](https://www.json.org/json-en.html)
* [OpenGraph](https://ogp.me)