> For the complete documentation index, see [llms.txt](https://docs.snomed.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.snomed.org/education/snomed-ct-education-editorial-guide/readme/concept-model-overview.md).

# Introduction to Concept Model

<mark style="color:$danger;">**This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.**</mark>

The *Concept Model* is used to specify logical definitions of *SNOMED CT* concepts. It is based on a combination of formal logic and editorial rules and includes the attributes and values that may be applied to concepts.

| Definition                                                                                                | Note                                                                                                                                                                                                                                                                   |
| --------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| The set of rules that determines the permitted sets of relationships between particular types of concepts | The Concept Model specifies the attributes that can be applied to concepts in particular domains and the ranges of permitted values for each of these attributes. There are also additional rules on the cardinality and grouping of particular types of relationships |

#### Features

{% content-ref url="/pages/0QWDiE7Kg4KhMUPJbEyB" %}
[Root and Top-level Concepts](/education/snomed-ct-education-editorial-guide/readme/concept-model-overview/root-and-top-level-concepts.md)
{% endcontent-ref %}

{% content-ref url="/pages/NO6Ua082vgeNSK5ek2md" %}
[Attributes](/education/snomed-ct-education-editorial-guide/readme/concept-model-overview/attributes.md)
{% endcontent-ref %}

{% content-ref url="/pages/wxZp8h5vpg0RvmCK75jC" %}
[Defining Characteristics](/education/snomed-ct-education-editorial-guide/readme/concept-model-overview/defining-characteristics.md)
{% endcontent-ref %}

{% content-ref url="/pages/7z8Ofxn33RkY59qTPEec" %}
[Qualifying Characteristics](/education/snomed-ct-education-editorial-guide/readme/concept-model-overview/qualifying-characteristics.md)
{% endcontent-ref %}

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