# Canonical Source

> The requirement that each piece of knowledge have one authoritative definition rather than copies.

Record: `lexicon:canonical-source`
Kind: constraint
Layer: [Structural Core](https://banes-lab.com/records/layer/structural-core.md)
Canonical: https://banes-lab.com/ontology/lexicon#lexicon-canonical-source

Listed in [Lexicon terms](https://banes-lab.com/api/records/lexicon.md), after [YAGNI](https://banes-lab.com/records/lexicon/yagni.md) and before [Contract Compatibility](https://banes-lab.com/records/lexicon/contract-compatibility.md).

## Category

- [Core Modular Design](https://banes-lab.com/records/lexicon-category/core-modular-design.md)

## Required by

- [Do Not Repeat Yourself](https://banes-lab.com/records/architecture/duplicate-code.md)

## Linked from

- [Core Modular Design](https://banes-lab.com/ontology/principles/architecture-category-core-modular-design.md)