AEO, GEO, AIO, LLMO and AI SEO: the terms, explained

What does each term stand for?

• ·AEO, answer engine optimisation: being the answer when someone asks a search engine or an AI assistant a direct question. The oldest of the five.
• ·GEO, generative engine optimisation: being cited or named in answers that engines write themselves, such as ChatGPT, Gemini, Perplexity and Google's AI Overviews and AI Mode.
• ·AIO, AI optimisation: the loosest label, used for optimising for AI answers in general. The same three letters are easy to read as AI Overviews, Google's AI summaries, so ask which one someone means.
• ·LLMO, large language model optimisation: the same idea framed around the models themselves. Some people use it to include what a model learned about you in training, not only what it finds by searching.
• ·AI SEO: the plain-English umbrella. It also gets used for something different, using AI tools to do SEO work, so check the context.

What does GEO stand for, and where did it come from?

GEO stands for generative engine optimization. Unlike the other terms, it has a clear birth: a research paper by Pranjal Aggarwal, Vishvak Murahari, Tanmay Rajpurohit, Ashwin Kalyan, Karthik Narasimhan and Ameet Deshpande, first posted to arXiv in November 2023 and accepted at KDD 2024, a major data-mining conference.

The paper defined generative engines as systems that write an answer from several sources, and GEO as a way for content creators to raise their visibility in those answers. It introduced a benchmark of queries, GEO-bench, and reported that its methods could raise visibility by up to 40%. The best methods were adding quotations, statistics and cited sources; keyword stuffing gave little or no improvement. The authors tested on their own engine and on Perplexity.ai, and found that what works varies by subject.

Where did AEO come from?

AEO has no founding paper. It grew out of the late 2010s, when Google's featured snippets and voice assistants started giving one answer instead of a list of links. In January 2018 Google wrote that featured snippets were especially helpful for people searching on mobile or by voice, and that Google Assistant and Google Home read them aloud and credited the source. Search marketers began writing about optimising for that single answer, and called it answer engine optimisation.

Several practitioners say they coined the term around 2017 or 2018. We found no independent record that settles who was first, so we do not credit anyone. What is clear is that the name was ready and waiting when ChatGPT and Perplexity arrived, and it was quickly applied to them.

What about LLMO, AIO and AI SEO?

LLMO has no agreed origin either. One early, prominent use came from Bruce Schneier and Judith Donath, writing in The Atlantic in April 2024, who predicted that SEO would “morph into LLMO: large-language-model optimization”. Vendors and consultants have since used it as a synonym for GEO, sometimes stretched to cover a model's training data.

AIO and AI SEO are generic labels rather than coined terms. AIO is the vaguest of the set, partly because of the overlap with AI Overviews, which Google rolled out to everyone in the US in May 2024. AI SEO is the easiest for a buyer to understand, and the most ambiguous, because it also describes AI-powered SEO tools.

AEO vs GEO: which terms do people actually search for?

We compared the full phrases in Google Trends on 20 October 2026, worldwide, over the previous 12 months. Trends shows relative interest on a 0 to 100 scale, not search volumes, so treat these as our estimate of the order, not exact sizes.

• ·“AI SEO”: average interest 59, far ahead of everything else.
• ·“generative engine optimization”: 9.
• ·“LLM optimization”: 8, though the phrase also covers making the models themselves run faster, so it overstates interest.
• ·“answer engine optimization”: 5.
• ·“LLMO”: 2.
• ·In the US alone the order was the same: 59, 11, 10, 7 and 1.
• ·The bare acronyms are hard to measure: GEO also means geography and geolocation, and AEO and AIO collide with other brands and abbreviations.
• ·So GEO is ahead of AEO in searches for the full name, and “AI SEO” leads both, though some of its interest comes from people looking for AI-powered SEO tools rather than for AI visibility.

Why is it one job in practice?

Whatever the label, the work is the same four things: make your site readable to AI crawlers, write answer-first pages an engine can quote, earn mentions on the reviews, lists and publications those engines cite, and measure how often you are named across repeated runs. No engine publishes separate rules for AEO, GEO or LLMO. Google says there are no extra requirements or special optimisations for appearing in AI Overviews or AI Mode beyond sound SEO.

Use the term your buyers use. On this site we say AEO and GEO together, and our guide “AEO vs GEO vs SEO” covers how that work relates to ordinary SEO. Be wary of anyone who sells AEO, GEO and LLMO as three separate services: you would be paying three times for one piece of work.

How Seamwire approaches it

Whatever you call it, we start the same way: a free AI visibility check on your own market, showing which engines name you for real buyer questions and who they name instead. If the gap is worth closing, an audit and then a programme follow, with your named-share and AI-referred leads reported every month.