The AI Search Glossary: GEO, AEO, LLM SEO and More

The AI search world is full of overlapping acronyms: GEO, AEO, LLM SEO, AI SEO, and more. Most describe the same shift, earning AI search visibility inside AI-generated answers, with small differences in emphasis.

This glossary defines the terms that actually matter in plain English, so you can read, write, and plan without the jargon getting in the way. Each entry leads with a direct definition.

The optimization disciplines

These terms mostly describe the same work. Here is what each one emphasizes.

GEO (Generative Engine Optimization).

The practice of optimizing your content so that generative AI engines mention or cite your brand in their answers. It centers on clarity, structure, and trust signals rather than keyword rankings. GEO is the most widely used umbrella term for this work.

AEO (Answer Engine Optimization).

Optimizing content to become the direct answer in AI summaries and answer engines. It overlaps almost entirely with GEO, with a slightly stronger focus on direct-answer and snippet formats.

LLM SEO.

SEO aimed specifically at large language models. The goal matches GEO, framed around how LLMs retrieve and choose sources. The terms are often used interchangeably.

AI SEO.

A broad, informal label for any SEO adapted to AI search. It usually means the same thing as GEO, preferred by people who want to keep “SEO” in the name.

GAIO (Generative AI Optimization).

A less common synonym for GEO. Same core idea, different acronym.

In short, these overlap heavily. Pick one term and use it consistently. GEO is the safest default because it is the most widely recognized.

Visibility metrics and concepts

These metrics replace the rankings and clicks of classic SEO, which is the heart of how AI search visibility differs from traditional SEO.

How often and how prominently AI engines mention or cite your brand when people ask questions. It is the headline metric every term in this glossary tries to improve.

• Citation. When an AI engine links to your page as a source within its answer. Citations tend to drive higher-intent clicks, since the reader arrives already informed.
• Mention. When an AI engine names your brand in an answer without linking to you. Still valuable for awareness and consideration.
• Share of voice. Your citation share compared with competitors across a set of tracked prompts. It is the AI version of market share.
• Sentiment. Whether an AI frames your brand positively, neutrally, or negatively when it appears in an answer.
• Query coverage. The share of relevant prompts where your brand shows up at all. Low coverage points to content gaps.
• Hallucination. When an AI states something false or invents a source. It matters because engines can misdescribe or misattribute brands.

AI engines and surfaces

• Answer engine. Any tool that returns a synthesized answer instead of a list of links, such as ChatGPT, Perplexity, or Gemini.
• AI Overviews. Google's AI-generated summaries that appear above the classic results for many queries.
• AI Mode. Google's fully conversational search experience, where you chat with the results rather than scan links.
• The major engines. ChatGPT, Google AI Overviews, Gemini, Perplexity, Claude, and Copilot are the platforms most worth tracking today.

Technical terms

• RAG (Retrieval-Augmented Generation). When an AI retrieves live web content to ground its answer and then cites sources. It is why fresh, crawlable content gets picked up.
• AI crawler. A bot such as GPTBot, PerplexityBot, or ClaudeBot that fetches your content for an AI engine. Blocking them removes you from those answers.
• llms.txt. A proposed text file that tells AI systems how to access and use your site's content, similar in spirit to robots.txt.
• Schema markup. Structured data added to your pages that gives engines explicit, machine-readable context about your content and brand.
• Entity. A distinct brand, product, person, or concept that engines recognize and connect, beyond simple keyword matching.
• Query fan-out. When an engine runs several related searches at once to answer a single prompt, pulling from multiple sources.
• Zero-click. A search that ends without any click because the answer appears directly in the results or the AI response.

Frequently asked questions

Are GEO, AEO, and LLM SEO the same thing?

Mostly yes. They all describe optimizing to appear in AI answers. The differences are emphasis, not substance, and GEO is the most common umbrella term.

What is the difference between GEO and SEO?

SEO aims to rank a page in search results. GEO aims to get your brand cited inside AI answers. They overlap, since AI engines often pull from high-ranking pages.

Which term should I use?

Pick one and stay consistent. GEO is the safest default because it is the most widely recognized across the industry.

Is AEO different from AI SEO?

Only slightly. AEO leans toward direct-answer formats, while AI SEO is a broader, informal label. In practice, they target the same outcome.

Do these replace traditional SEO?

No. They build on it. Strong SEO feeds AI visibility, because engines lean on trusted, high-ranking pages when they choose sources.

The bottom line

The vocabulary keeps growing, but the core idea is simple: AI engines now answer questions directly, and you want to be the brand they name. Knowing these terms is step one, and understanding why AI search visibility matters for your brand is the strategy behind them.

See exactly where your brand shows up across ChatGPT, Gemini, and Perplexity. Start tracking with Netfuel, or see plans and pricing.