# etendue

> conserved property of the light in an optical system which characterizes how "spread out" the light is in terms of angle and area

**Wikidata**: [Q1370994](https://www.wikidata.org/wiki/Q1370994)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Etendue)  
**Source**: https://4ort.xyz/entity/etendue


## References

1. Freebase Data Dumps. 2013