# category (group)

a set of things that share a kind

- Computed level: L9 (depth in the emergence graph, not abstraction)
- Status: review  ·  Domain: category  ·  Arena: EmergenceLexicon

## Emergence
**Emerges from:** [sets](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-sets.grouped), [type](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-type.category), [pattern](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-pattern.regularity), [share](https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-share.distribution)

**Through:** when a set of things is bounded together because they are of the same kind, a category emerges

**Novel properties:**
- shared kind identification
- cross-instance similarity
- class membership

## Examples
- The Linux kernel classifies system calls into groups like 'file operations' or 'process control'. *(computing)*
- Biologists group all felines under the taxonomic category Felidae based on shared morphological traits. *(biology)*
- The International Building Code separates structures into occupancy categories such as 'residential' or 'assembly'. *(engineering)*

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*Canonical: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-category.group*  
*Structured data: https://emergencemachine.com/tools/lexicon/what-is-the-meaning-of-category.group.json*  
*Every definition provably resolves to space, time, energy and pattern.*