# Simple Expression

Precoordinated expressions consist of a single concept identifier, followed optionally by any term that is associated with that concept. While the use of a term is not mandated, it is often preferable to include preferred term from an appropriate dialect within the expressions to improve the human-readability of the expression.

For example: [73211009 | Diabetes mellitus|](http://snomed.info/id/73211009)

As mentioned, the syntax does not require a term to be used with each concept identifier, so the following is also a valid expression:

```
73211009 | diabetes mellitus|
```

<a href="https://docs.google.com/forms/d/e/1FAIpQLScTmbZIf0UEQwYDkY27EEWBkaiYkHSbR0_9DmFrMLXoQLyL7Q/viewform?usp=pp_url&#x26;entry.1767247133=Compositional-Grammar-Specification&#x26;entry.670899847=Simple%20Expression" class="button primary">Provide Feedback</a>


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.snomed.org/snomed-ct-specifications/snomed-ct-compositional-grammar-specification/examples/6.1-simple-expression.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.