# equivalence

## equivalence

**This is an abbreviation for semantic equivalence.**

## semantic equivalence

The relationship between two classes that have the same logical meaning.

#### Notes

* The equivalent classes may be represented in different ways for example as SNOMED CT concept definitions, SNOMED CT expressions, or axioms expressed using a syntax such as OWL Functional Syntax.
* Semantic equivalence is represented by the Ξ symbol or by a sequence of three equals signs === .

#### Example

* The expression below asserts that the concept [80146002 | Appendectomy|](http://snomed.info/id/80146002) has *semantic equivalence* with [71388002 | Procedure|](http://snomed.info/id/71388002) with method [129304002 | Excision - action|](http://snomed.info/id/129304002) applied to the direct site [66754008 | Appendix structure|](http://snomed.info/id/66754008) .

[80146002 |Appendectomy|](http://snomed.info/id/80146002)\
\=== [71388002 |Procedure|](http://snomed.info/id/71388002) :\
{ [405813007 |Procedure site - Direct|](http://snomed.info/id/405813007) = [66754008 |Appendix structure|](http://snomed.info/id/66754008) ,\
[260686004 |Method|](http://snomed.info/id/260686004) = [129304002 |Excision - action|](http://snomed.info/id/129304002) }

## Alternatives

* **Concept equivalence**
* **Equivalence**

## Disambiguation

Not to be confused with:

* Word equivalents
* Phrase equivalents

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