# Definition **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.** A *definition* is a textual description applied to some SNOMED CT concepts that provides additional information about the intended meaning or usage of the concept. Definitions are not mandated and are considered for addition on a case-by-case basis, and if required, to differentiate a concept from its related concepts. Adding a definition to a concept provides additional clarity on its context of use. It enhances the definition provided by the modeled relationships whereby a term can be sufficiently defined logically, but the words, which is how many look for and interpret meaning, may imply more or less specificity. {% hint style="info" %} The definition should never be contradictory to the modeling. {% endhint %} Definitions must: * be written as complete sentences, * begin with a capital letter, * end with a period, * apply a case sensitivity of *Entire term case* *sensitive* (CS). For example, * The definition for the concept 11530004 | Brittle diabetes mellitus (finding)| is: * *Frequent, clinically significant fluctuations in blood glucose levels both above and below levels expected to be achieved by available therapies.* The language acceptability default for a single Definition description is *Preferred.* A definition with varying US and GB English descriptions are each applied with the respective language acceptability. For example, ``` 1332358007 |Full schwannomatosis (disorder)| ```

Definition of 1332358007 |Full schwannomatosis (disorder)| with US and GB English acceptability values.

## Consideration for text definition A text definition should be considered where a concept references the obscure or unusual. As an example, *raised blood pressure* is a commonly used phrase, which, in itself, is ambiguous. *Raised* can mean: 1) higher than a previous measurement, 2) on the high side of normal range, or 3) above reference range. Because of that ambiguity, a full definition created by logical model may be impossible, so a text definition could be used to encourage consistent use of the term. The following principles for definition creation are summarized below from ISO-704, *Terminology work — Principles and methods* :

Principle	Explanation
Clarity	Avoid ambiguity or overly complex language.
Conciseness	Be as brief as possible without sacrificing meaning.
Consistency	Use a consistent structure and vocabulary.
Non-circular	Do not use the term in the definition.
Genus + Differentia	Define by broader category + distinguishing features.
Context-aware	Include notes or usage context if necessary.

In summary, if a term may be interpreted in multiple ways, but is intended to mean only one way in SNOMED CT, it needs a definition. However, ultimate source of truth for meaning remains with the FSN. {% hint style="warning" %} URLs that point to definition sources are unacceptable. External references, such as ISBN and PubMed identifiers, are not allowed in SNOMED CT concept definitions. {% endhint %} Provide Feedback --- # 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/education/snomed-ct-education-editorial-guide/readme/authoring/general-naming-conventions/descriptions/definition.md?ask= ``` 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.