> ## Documentation Index
> Fetch the complete documentation index at: https://private-7c7dfe99-postgresql-tls-support.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Core concepts

> Learn Core Concepts of how ClickHouse works

In this section of the documentation,
you will learn some of the core concepts of how ClickHouse works.

<CardGroup cols={2}>
  <Card title="Glossary" icon="book-open" href="/concepts/core-concepts/glossary">
    Commonly used ClickHouse words and phrases, and their definitions.
  </Card>

  <Card title="Table parts" icon="cubes" href="/concepts/core-concepts/parts">
    Learn what table parts are in ClickHouse.
  </Card>

  <Card title="Table partitions" icon="table-cells-large" href="/concepts/core-concepts/partitions">
    Learn what table partitions are and what they're used for.
  </Card>

  <Card title="Table part merges" icon="code-merge" href="/concepts/core-concepts/merges">
    Learn what table part merges are and what they're used for.
  </Card>

  <Card title="Primary indexes" icon="key" href="/concepts/core-concepts/primary-indexes">
    How ClickHouse's sparse primary index helps efficiently skip unnecessary data during query execution.
  </Card>

  <Card title="Query parallelism" icon="bolt" href="/concepts/core-concepts/query-parallelism">
    How ClickHouse parallelizes query execution using processing lanes and the `max_threads` setting.
  </Card>

  <Card title="Architectural Overview" icon="graduation-cap" href="/concepts/core-concepts/academic-overview">
    A concise academic overview of all components of the ClickHouse architecture, based on our VLDB 2024 scientific paper.
  </Card>
</CardGroup>