> For the complete documentation index, see [llms.txt](https://docs.annolab.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.annolab.ai/annotations-and-relations.md).

# Annotations and Relations

- [Annotations](https://docs.annolab.ai/annotations-and-relations/annotations.md): Annotations one of the fundamental building blocks of extracted data. They say that a portion of a source has some special meaning
- [Canonical Tags](https://docs.annolab.ai/annotations-and-relations/canonical-tags.md): Unique entities described by a set of annotations
- [Instruments](https://docs.annolab.ai/annotations-and-relations/instruments.md): Instruments are a special format produced by Export Instruments and Search Instruments
- [Relations](https://docs.annolab.ai/annotations-and-relations/relations.md)
- [Annotation Layers](https://docs.annolab.ai/annotations-and-relations/annotation-layers.md): Annotation layers are containers for annotations and can be used to "version" annotations and experiment outputs.