AIO vs AEO vs GEO: every AI optimization acronym explained
·7 min read
AI optimization is the work of getting your site quoted, cited or named when an AI system writes the answer, and AIO, AEO, GEO, LLMO and GSO are mostly rival labels for that one job. AEO is the page-level part, getting a passage lifted as the direct answer. GEO, along with its near-synonyms LLMO and GSO, covers whether ChatGPT, Perplexity, Gemini and Google's AI features mention your brand and cite your pages. AIO is the slipperiest of the lot, because SEO people also use it to mean Google's AI Overviews.
Only one of these distinctions changes the work you do. The rest are relabels, usually by someone who wants a category of their own to sell. Our own name stacks three of the acronyms, so I understand the urge.
Every AI search acronym at a glance
| Acronym | Stands for | What it targets | Who uses the term | Status |
|---|---|---|---|---|
| AIO | AI optimization, or AI Overviews | Any AI answer, or Google's AI Overviews alone | Agencies, and rank trackers as shorthand for AI Overviews | Ambiguous, ask which one |
| AEO | Answer engine optimization | The single passage an engine lifts as the answer | SEOs and content teams | Common |
| GEO | Generative engine optimization | Mentions and citations in AI-written answers | Researchers, AI visibility tools, agencies | Common, with the clearest origin |
| LLMO | Large language model optimization | How chatbots describe and recommend a brand | Some agencies and tool vendors | Synonym for GEO |
| GSO | Generative search optimization | AI answers inside search engines | A few agencies | Rare synonym for GEO |
| SGE | Search Generative Experience | Google's AI answer experiment in Search Labs | Google, from 2023 | Retired, became AI Overviews |
| AI SEO | SEO for AI search, or SEO done with AI | Depends on who is talking | Nearly everyone | Loose umbrella term |
What is AI optimization (AIO)?
AI optimization, shortened to AIO, means making a website easy for AI systems to read and cite. The trouble is the abbreviation. In SEO trade writing and rank tracking tools, AIO usually means Google's AI Overviews, so an "AIO report" often covers one Google feature and says nothing about ChatGPT or Perplexity. Outside marketing, AI optimization also means making machine learning models faster or cheaper to run, which has nothing to do with your website.
Google's own guide on the subject lives at a URL ending in ai-optimization-guide, and its verdict is blunt. Optimizing for generative AI search, it says, is "still SEO". The same guide says you need no AI text files, special markup or Markdown copies of your pages to appear in Google Search.
When an agency proposal says AIO, ask whether it means AI Overviews only or every assistant your buyers use. The scope and the price should follow from the answer.
What is AEO (answer engine optimization)?
Answer engine optimization is shaping one page so an engine can lift a passage from it and show that passage as the answer. Its targets are extractive formats like featured snippets, voice assistant answers and the quoted lines inside an AI response.
AEO is page-level work, done one URL at a time. Put the question in a heading in the words people search with. Answer it in the first sentence underneath. Make that answer specific enough to stand alone if it gets copied out of context, and use a table when you compare things. A writer can do most of it without touching the server.
What is GEO (generative engine optimization)?
Generative engine optimization is getting your brand mentioned and your pages cited when a large language model builds an answer from several sources. The term comes from GEO: Generative Engine Optimization, a paper by Pranjal Aggarwal and five co-authors, posted to arXiv in November 2023 and accepted to KDD 2024. The authors reported that their methods raised a source's visibility in generated answers by up to 40%.
GEO is site-level and off-site work, and that is the real difference from AEO. A generative engine has to be allowed to fetch your pages, see the content without running JavaScript, recognize your brand as one entity and find other sites that mention you. Rewriting a paragraph fixes none of those. A blocked crawler or a page that renders empty for bots will sink the best-written answer on the site.
LLMO, GSO and AI SEO: same work, different label
LLMO, GSO and AI SEO describe the same work as GEO under other names.
LLMO stands for large language model optimization. I could not find a paper or a person who coined it. Some practitioners use LLMO for influencing what models learn during training and keep GEO for what they retrieve at answer time. That split is real in theory, but you control almost nothing about training data, so the practical work ends up identical to GEO. Our guide to LLM SEO and how chatbots pick sources goes deeper on LLMO.
GSO, generative search optimization, narrows GEO to AI answers inside search engines, such as AI Overviews and AI Mode. You will see it rarely, and nothing about the work changes.
AI SEO is the loosest term on the list. Some people who say it mean SEO for AI search, and others mean ordinary SEO done with AI writing tools. Read what AI SEO means if you need to pin down which one a vendor is selling.
What happened to SGE?
SGE, the Search Generative Experience, was the name of Google's AI answers while they were an experiment, and the name is retired. Google introduced SGE on May 10, 2023 as an opt-in experiment in Search Labs. On May 14, 2024, Google began rolling out AI Overviews to everyone in the U.S. and said people had already used AI Overviews billions of times through that Search Labs experiment.
Google then introduced AI Mode on March 5, 2025, again as a Labs experiment, and it is a separate product from AI Overviews. Our post on AI Overviews vs AI Mode covers how the two differ. If a course or a proposal still tells you to optimize for SGE, check when it was written.
AIO vs AEO vs GEO: the differences that matter in practice
The difference that matters is page versus site. AEO is page-level answer extraction, and GEO is site-level and off-site visibility in AI answers. AIO, LLMO, GSO and AI SEO sit on top of those two as umbrella names or synonyms.
That settles AIO vs AEO too. If AIO means AI optimization, it is the umbrella and AEO is one part of it. If AIO means AI Overviews, it is one place where both AEO and GEO work pay off.
| AEO work | GEO work | |
|---|---|---|
| Unit of work | One page, one passage | The whole site and what other sites say about it |
| Typical fixes | Question headings, answer-first sentences, tables, schema | AI crawler access, server-rendered HTML, consistent Organization markup, mentions on sites AI answers cite |
| Who does it | Writers and editors | Developers, plus whoever handles PR and partnerships |
| How you check it | Read each section as a standalone quote | Sample AI answers, compare raw and rendered HTML, audit brand data |
Measurement splits along the same line. For Google's AI features, Search Console's Generative AI performance report has been open to all sites since August 31, 2026. It shows impressions only, with AI Overviews and AI Mode combined. For ChatGPT, Perplexity and Gemini, you sample the prompts your buyers use and record what comes back.
Google's guide names AEO and GEO as popular terms, then spends a whole section on popular tactics you don't need. Read that section before you pay for any acronym. For how SEO fits next to the two, see our comparison of AEO, GEO and SEO with the order to do them in.
My advice is to keep two words on your team. Use AEO for page edits and GEO for everything else. A team that tracks five acronyms tends to end up with five dashboards and the same robots.txt bug.
Check your AI visibility with GEO tools
Our GEO tools cover the site-level and off-site half of this glossary. There are eleven, each runs on its own, and each costs a fixed number of credits per run, from 5 to 160.
AI Crawler View (8 credits) compares a page's raw HTML with the same page rendered in a headless browser and lists the content, headings, prices, structured data, links and metadata that only appear after JavaScript runs. Brand Entity Checker (8 credits) checks that your brand name matches across Organization and WebSite markup, og:site_name, the web app manifest and llms.txt. It also checks that your logo loads, that your sameAs profiles exist and whether a Wikidata item lists your site.
AI Answer Visibility (120 credits) asks ChatGPT, Perplexity and Gemini your customer's question with web search on. It shows whether each answer names your brand, where you rank among the brands named, whether it cites your site, and which brands and sites it recommends instead.