---
title: "What is an embedding?"
description: "An embedding is a numeric vector that places a passage, frame, or other piece in a space where similar items sit near each other."
url: "https://pixeltable.com/learn/what-is-an-embedding"
updated: "2026-09-29"
vertical: "Retrieval"
doc: "https://docs.pixeltable.com/datastore/embedding-index"
---

# What is an embedding?

An embedding is a numeric vector that places a passage, frame, or other piece in a space where similar items sit near each other.

Updated: 2026-09-29


## On this page

- [How it works](https://pixeltable.com/learn/what-is-an-embedding#how-it-works)
- [What it is not](https://pixeltable.com/learn/what-is-an-embedding#what-it-is-not)
- [Comparison](https://pixeltable.com/learn/what-is-an-embedding#comparison)
- [Where Pixeltable fits](https://pixeltable.com/learn/what-is-an-embedding#where-pixeltable-fits)
- [Questions](https://pixeltable.com/learn/what-is-an-embedding#questions)

## How it works {#how-it-works}


- A model reads the piece and writes a vector.
- Pieces with similar meaning land near each other.
- Search ranks neighbors of a query vector. The vector is not a substitute for keeping the source.

## What it is not {#what-it-is-not}

It is not the original file, and it is not a keyword token.

## embedding: this, and the thing it is confused with {#comparison}

|  | This | Not this |
| --- | --- | --- |
| Represents | Meaning as numbers | The raw file |
| Comparable across | Pieces from the same model | Vectors from two unrelated models |
| You still store | The passage or frame | Only the vector |

## Where Pixeltable fits {#where-pixeltable-fits}

Pixeltable stores the source column and can declare an embedding index on it, so the vector is derived, not a second copy you load.

## Questions {#questions}

### How does embedding work? {#faq-1}

A model reads the piece and writes a vector. Pieces with similar meaning land near each other. Search ranks neighbors of a query vector. The vector is not a substitute for keeping the source.

### What is embedding often confused with? {#faq-2}

It is not the original file, and it is not a keyword token.

## In the blog

- [Beyond AVG(): Building Custom Aggregation Functions for AI Workflows with Pixeltable UDA](https://pixeltable.com/blog/beyond-avg-custom-aggregations-uda)
- [Why Your RAG Is Wrong: The Ultimate Guide to Production-Ready Embedding Management](https://pixeltable.com/blog/embedding-management-guide)
- [DocuVision: PDF Q&A Without LangChain Plus a Vector DB](https://pixeltable.com/blog/docuvision-pdf-chart-qa)
- [Pixeltable April 2026 Release Highlights](https://pixeltable.com/blog/pixeltable-april-2026-release-highlights)
- [Pixeltable January 2026 Release Highlights](https://pixeltable.com/blog/pixeltable-january-2026-release-highlights)
- [Build Production Document RAG Pipelines with Pixeltable](https://pixeltable.com/blog/document-pdf-processing-rag-pixeltable)

## Related

- [Documentation](https://docs.pixeltable.com/datastore/embedding-index)
- [Why Your RAG Is Wrong: The Ultimate Guide to Production-Ready Embedding Management](https://pixeltable.com/blog/embedding-management-guide)
- [Production RAG](https://pixeltable.com/use-cases/production-rag-implementation)
- [semantic-search](https://pixeltable.com/tools/semantic-search)