AI Search Glossary
Plain-English definitions of the terms that matter in AI search: GEO, AEO, AI Overviews, llms.txt, Share of Model, Zero-Click Search, Citation Rate, Prompt Tracking, AI Crawlers, RAG, the EU AI Act and more.
GEO
GEO (Generative Engine Optimization) is the discipline of making your brand visible, correctly described and recommended inside AI-generated answers from ChatGPT, Perplexity, Gemini and AI Overviews.
AEO
AEO (Answer Engine Optimization) is the practice of getting your brand and content cited inside the direct answers of AI engines — ChatGPT, Perplexity, Gemini and Google AI Overviews.
Answer Engine
An answer engine answers questions directly instead of returning a list of links — ChatGPT, Perplexity, Gemini, Copilot and Google AI Overviews.
AI Overviews
Google AI Overviews are AI-generated summaries shown above search results.
RAG
RAG (retrieval-augmented generation) is how AI engines fetch live web pages at answer time instead of relying on training memory — and why fresh content can enter answers fast.
AI Crawlers
AI crawlers are bots that fetch web pages for AI training and retrieval — GPTBot, ClaudeBot, PerplexityBot and more. Block them and you may vanish from AI answers.
llms.txt
llms.txt is a proposed Markdown file at the root of a website that tells AI models what the site is about and which pages matter most — a sitemap for language models.
Share of Model
Share of model measures how often AI engines mention your brand versus competitors in a category — the AI-era equivalent of share of voice.
Citation Rate
Citation rate is the share of AI answers in your category that cite your domain as a source — the difference between being talked about and being pointed to.
AI Brand Mentions
AI brand mentions are the times ChatGPT, Perplexity, Gemini and AI Overviews name your brand in their answers — whether they link to you or not.
Prompt Tracking
Prompt tracking means asking a fixed set of buyer questions to AI engines on a schedule and recording whether your brand is mentioned — rank tracking for the AI era.
Zero-Click Search
Zero-click search is when a search ends without the user clicking any website — the answer is consumed on the results page itself.
EU AI Act
The EU AI Act is the European Union's risk-based law for AI, phasing in from 2025 — transparency rules that shape how chatbots, AI content and answer engines must behave.
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