# Schema/Ontology

> A formal definition of the entity types and relationship types a knowledge graph may contain.

Record: `lexicon:schema-ontology`
Kind: artifact
Layer: [Correctness Core](https://banes-lab.com/records/layer/correctness-core.md)
Canonical: https://banes-lab.com/ontology/lexicon#lexicon-schema-ontology

Listed in [Lexicon terms](https://banes-lab.com/api/records/lexicon.md), after [Retriever](https://banes-lab.com/records/lexicon/retriever.md) and before [Tool Interface](https://banes-lab.com/records/lexicon/tool-interface.md).

## Category

- [Model Architecture](https://banes-lab.com/records/lexicon-category/model-architecture.md)

## Required by

- [Knowledge Graphs](https://banes-lab.com/records/architecture/knowledge-graphs.md)

## Linked from

- [Model Architecture](https://banes-lab.com/ontology/principles/architecture-category-model-architecture.md)
- [Model Architecture](https://banes-lab.com/ontology/lexicon/lexicon-category-model-architecture.md)