> 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/snomed-international-documents/snomed-ct-glossary/d/description/description-logic.md).
# description logic
## description logic
A representation of semantic knowledge that allows formal reasoning to be applied based on axioms.
#### Notes
* *Description logic* definitions of SNOMED CT concepts are represented in two ways, as:\
\* OWL Functional Syntax in an OWL Expression Reference Set\
\* Defining relationships in the Relationship File.
* The formal rules of *description logic* can be applied to concept definitions by software tools (description logic classifiers) to interpret the meaning of concepts. This enables confirmation of the logical integrity of the terminology, and can also be used to support meaning-based retrieval from records containing SNOMED CT expressions or concepts.
## Alternatives
* **DL**
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