The AEO glossary
50 terms behind AI visibility, defined in plain English: what each one means, why it matters for whether AI engines recommend your business, and where the facts come from. Crawler behaviour and engine claims are cited to primary sources, with the date we checked them.
12 terms
Core concepts
Answer engine optimisation (AEO)
Answer engine optimisation (AEO) is the practice of making sure AI assistants such as ChatGPT, Claude, Gemini, Perplexity, Google AI Overviews and AI Mode mention, cite and accurately describe your business when someone asks them a buying question.
Generative engine optimisation (GEO)
Generative engine optimisation (GEO) is another name for the discipline of earning visibility and citations in AI-generated answers.
AI visibility
AI visibility is whether, and how often, AI engines mention or cite your business when people ask the questions your customers actually ask.
Answer engine
An answer engine is a system that responds to a question with a direct answer rather than a page of links.
Large language model (LLM)
A large language model (LLM) is the AI system behind engines like ChatGPT, Claude and Gemini: a model trained on enormous amounts of text that predicts fluent answers to prompts.
AI citation
An AI citation is when an answer engine names or links your website as a source for part of its answer.
Brand mention
A brand mention is any appearance of your business name in an AI engine's answer, with or without a link.
Share of voice (AI)
Share of voice in AI answers is the percentage of mentions that belong to you, out of every business mention the engines hand out across your tracked buyer questions.
Zero-click search
A zero-click search is one where the user gets what they need without visiting any website: the answer appears on the search page or in the assistant's reply and the journey ends there.
Conversational search
Conversational search is finding things through a back-and-forth dialogue with an AI assistant instead of a one-shot query.
Query fan-out
Query fan-out is the technique Google documents behind AI Overviews and AI Mode: one question is expanded into multiple related searches across subtopics and data sources, and the answer is assembled from all of them.
Grounding
Grounding is when an AI engine retrieves live sources, usually via a search index, and bases its answer on them instead of relying purely on training memory.
10 terms
AI engines and crawlers
AI crawler
An AI crawler is a bot an AI company sends to fetch web pages.
GPTBot
GPTBot is OpenAI's training crawler.
OAI-SearchBot
OAI-SearchBot is the crawler OpenAI uses to surface websites in ChatGPT's search features.
ChatGPT-User
ChatGPT-User is the user agent OpenAI sends when a person's action inside ChatGPT or a custom GPT causes it to fetch a web page live.
ClaudeBot
ClaudeBot is Anthropic's training crawler: it collects public web content that may contribute to training Claude models.
Claude-SearchBot
Claude-SearchBot is the Anthropic crawler that analyses web content to improve the relevance and accuracy of Claude's search answers.
PerplexityBot
PerplexityBot is Perplexity's index crawler, designed, in Perplexity's words, to surface and link websites in its search results.
Perplexity-User
Perplexity-User is the agent Perplexity sends when a user's question triggers a live page visit.
Google-Extended
Google-Extended is a robots.txt product token that controls whether content Google crawls from your site may be used to train future Gemini models and for grounding Gemini's answers.
Googlebot
Googlebot is Google's main search crawler, and in the AI era it has a second job: the content it crawls and indexes for Search is the same content Google's AI Overviews and AI Mode draw on.
10 terms
Measurement
Prompt tracking
Prompt tracking is running a fixed panel of realistic buyer questions through AI engines on a schedule and recording every answer: who was mentioned, who was cited, and how each business was described.
AI visibility score
An AI visibility score condenses how often AI engines mention and cite your business, across a panel of buyer questions, into a single tracked number, typically out of 100.
Prompt set
A prompt set, also called a prompt panel or query set, is the curated list of questions a tracking tool puts to AI engines on every scan.
Citation rate
Citation rate is the percentage of tracked AI answers that cite your website as a source, measured separately from mention rate, the percentage that merely name you.
Answer position
Answer position is where your business appears within an AI answer: named first, listed mid-pack, or tacked on as an also-ran.
Hallucination
A hallucination is an AI engine stating something false with complete confidence.
AI sentiment
AI sentiment is how engines describe your business when they mention it: recommended warmly, listed neutrally, hedged with caveats, or actively warned against.
Competitor tracking
Competitor tracking in AEO means recording rivals' mentions and citations on the same prompt panel, in the same scans, as your own.
AI referral traffic
AI referral traffic is the visits your analytics attribute to AI surfaces: clicks on citations in ChatGPT, Perplexity or Gemini answers, arriving with referrers like chatgpt.com or perplexity.ai.
Bot log analysis
Bot log analysis is reading your server logs for AI crawler user agents to establish ground truth: which engines' bots visit you, which pages they read, how often, and whether anything is silently blocking them.
9 terms
Where SEO meets AEO
E-E-A-T
E-E-A-T stands for experience, expertise, authoritativeness and trustworthiness: Google's framework for what makes content credible.
YMYL (Your Money or Your Life)
YMYL, Your Money or Your Life, is Google's label for topics that can significantly affect a person's health, finances, safety or welfare.
Entity SEO
Entity SEO is the practice of making your business a clearly defined thing that machines can recognise: one consistent name, description, address and set of facts, repeated across your site, your listings and the wider web, so that search engines and AI models connect every scattered reference into one confident identity..
Schema markup
Schema markup is structured data added to web pages using the schema.org vocabulary, a shared standard maintained with the major search engines, that states facts in machine-readable form: this is an Organization, this its address; this is a Product, this its price; these are FAQs with these answers..
JSON-LD
JSON-LD is the most widely recommended format for schema markup: a small script block of structured data sitting in a page's HTML, separate from the visible content.
Knowledge Graph
The Knowledge Graph is Google's database of entities, people, places, organisations, and the facts and relationships connecting them, assembled from the web and licensed data sources.
Knowledge panel
A knowledge panel is the information box Google shows beside search results for entities in its Knowledge Graph: name, description, key facts and links, generated automatically from Google's understanding of available web sources.
Digital PR
Digital PR is earning coverage and mentions on websites you do not control: press, industry publications, roundups, directories, podcasts and forums.
Online reviews
Online reviews are customer ratings and write-ups on platforms like Google, Trustpilot and industry-specific sites.
9 terms
Technical
robots.txt
robots.txt is the plain-text file at your site's root that tells crawlers which parts of the site they may fetch, rule by rule, per user agent.
llms.txt
llms.txt is a proposed standard, published by Jeremy Howard in September 2024, for a markdown file at /llms.txt that gives AI systems a curated map of your site: a title, a summary and organised links to your most useful content.
User agent
A user agent is the identification string software sends when it requests a web page.
Crawlability
Crawlability is whether bots can actually fetch and read your pages: no blocking rules, no login walls, no challenge pages, responses fast enough that crawlers do not give up, and content present in the HTML the server sends.
JavaScript rendering
JavaScript rendering is when a page's content is assembled in the browser by scripts rather than delivered in the server's HTML.
sitemap.xml
sitemap.xml is the standard file listing the URLs you want crawlers to know about, with an optional lastmod date recording when each page last changed.
IndexNow
IndexNow is an open protocol through which a website pings participating search engines the moment a URL is added, changed or removed, instead of waiting to be recrawled.
Bing index
The Bing index is Microsoft's database of the crawled web, and it moonlights as infrastructure for AI answers: OpenAI documents that ChatGPT search uses its own index built by OAI-SearchBot and partners with third-party search providers, sharing disassociated queries with Bing among them.
nosnippet and snippet controls
nosnippet, data-nosnippet and max-snippet are Google's controls over what Search may quote from your pages, and Google documents that the same controls govern its AI features: AI Overviews and AI Mode show content under exactly the rules you set for snippets, with noindex removing a page from both..
Now see where you stand
Knowing the terms is the start. Send your domain and a named expert will run your business through all six engines, score what they say and email your report within 1 to 2 working days. Free, no card, no signup.
- ChatGPT
- Claude
- Gemini
- Perplexity
- Google AI Overviews
- Google AI Mode