---
title: AI Search & AEO Glossary · Elmo
description: "A plain-English glossary of AI search and answer engine optimization terms: AEO, GEO, LLMO, AI Overviews, citations, share of voice, RAG, and more."
canonical: https://www.elmohq.com/glossary
---

# The AI search glossary

The vocabulary of AI search and answer engine optimization, defined in plain English and cross-linked. Start anywhere.

## Core disciplines

- [Answer Engine Optimization](https://www.elmohq.com/glossary/answer-engine-optimization)AEO

  The practice of measuring and improving how often AI answer engines mention and cite your brand.

- [Generative Engine Optimization](https://www.elmohq.com/glossary/generative-engine-optimization)GEO, Generative SEO

  Optimizing content to appear inside AI-generated answers. Largely a synonym for AEO.

- [LLMO](https://www.elmohq.com/glossary/llmo)LLM Optimization, LLM SEO

  Large language model optimization: another name for the work of getting cited in AI answers.

- [AI visibility](https://www.elmohq.com/glossary/ai-visibility)

  How present your brand is across AI answers: how often it is mentioned, cited, and described accurately.

## Where AI answers appear

- [Answer engine](https://www.elmohq.com/glossary/answer-engine)

  A system that responds to a question with a synthesized answer rather than a page of links.

- [AI search engine](https://www.elmohq.com/glossary/ai-search-engine)

  A search product that returns AI-written answers with citations instead of a ranked list.

- [Google AI Overviews](https://www.elmohq.com/glossary/google-ai-overviews)

  AI-generated summaries Google shows above traditional results for many queries, built on its Gemini models.

- [Google AI Mode](https://www.elmohq.com/glossary/google-ai-mode)

  Google's full conversational search experience, a dedicated AI answer surface separate from AI Overviews.

- [ChatGPT Search](https://www.elmohq.com/glossary/chatgpt-search)

  ChatGPT's web-browsing mode, which retrieves live pages and cites them in its answers.

## What to measure

- [AI citation](https://www.elmohq.com/glossary/ai-citation)

  A source link an AI answer attributes information to. The clearest signal that your content shaped the answer.

- [Brand mention](https://www.elmohq.com/glossary/brand-mention)

  Any time an AI answer names your brand, whether or not it links to you.

- [Share of voice](https://www.elmohq.com/glossary/share-of-voice)

  The percentage of AI answers about your category in which your brand appears, measured against competitors.

- [Prompt volume](https://www.elmohq.com/glossary/prompt-volume)

  The number of prompts an engine is queried with when tracking visibility. Tools often meter usage by it.

- [Prompt tracking](https://www.elmohq.com/glossary/prompt-tracking)Prompt monitoring, Prompt set

  Running a fixed set of prompts across AI engines on a schedule to monitor how your brand appears over time.

- [AI visibility score](https://www.elmohq.com/glossary/visibility-score)

  An aggregate metric rolling mentions, citations, and competitor presence into a single number.

- [AI brand sentiment](https://www.elmohq.com/glossary/ai-brand-sentiment)

  How AI engines characterize your brand, not just whether they mention it.

## How engines work

- [Entity](https://www.elmohq.com/glossary/entity)

  A distinct thing a model recognizes, such as a company, product, or person, along with what it knows about it.

- [Structured data](https://www.elmohq.com/glossary/structured-data)Schema markup

  Machine-readable markup that labels what content is, helping engines extract and trust it.

- [llms.txt](https://www.elmohq.com/glossary/llms-txt)

  A proposed plain-text file that points AI crawlers to your most important content in Markdown.

- [Retrieval-augmented generation](https://www.elmohq.com/glossary/retrieval-augmented-generation)RAG

  A method where a model fetches relevant documents at answer time and writes from them.

- [Grounding](https://www.elmohq.com/glossary/grounding)

  Tying a model's answer to specific sources so claims can be traced and checked.

- [Hallucination](https://www.elmohq.com/glossary/hallucination)

  When a model states something false or invented with the same confidence as a fact.

- [AI crawler](https://www.elmohq.com/glossary/ai-crawler)

  A bot that fetches web pages for AI training or live retrieval, such as GPTBot or PerplexityBot.

- [Zero-click search](https://www.elmohq.com/glossary/zero-click-search)

  A search that ends without a click because the answer appears directly on the results surface.

- [Knowledge graph](https://www.elmohq.com/glossary/knowledge-graph)

  A structured map of entities and the relationships between them that engines use to ground answers.

- [Semantic search](https://www.elmohq.com/glossary/semantic-search)

  Search that matches on meaning rather than exact keywords, usually via embeddings.

- [Embedding](https://www.elmohq.com/glossary/embedding)

  A numeric representation of text that lets a model compare meaning and find related content.

- [Large language model](https://www.elmohq.com/glossary/large-language-model)LLM

  The kind of AI model behind answer engines, trained on large text corpora to predict and generate language.