> 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/disjunction.md).

# disjunction

## disjunction

An operator used to assert that at least one of two (or more) parts of a concept definition or expression constraint must be true.

#### Notes

* *Disjunction* can be represented by the**OR** operator. A disjunction of *A* with *B* , means that either *A* **OR** *B* must be true.
* *Disjunction* gives the same result as an **UNION** between the set of *concepts* or *expressions* for which *A* is true and the set of *concepts* or *expressions* for which *B* is true.

#### Example

* The following *expression constraint* is satisfied by clinical findings that are subtypes of either [19829001 | Disorder of lung (disorder)|](http://snomed.info/id/19829001) **OR** [301867009 | Edema of trunk (disorder)|](http://snomed.info/id/301867009) .

< [19829001 |Disorder of lung|](http://snomed.info/id/19829001) OR < [301867009 |Edema of trunk|](http://snomed.info/id/301867009)

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