The acronym pile has gotten ridiculous. Walk into any AI search agency pitch in 2026 and you will hear AEO, GEO, AIO, LLMO, and GSO used in a single deck, often as if they all mean the same thing. They do not. The vendors using them interchangeably are signaling something specific: they have not done the work to know the difference.
Here is the actual taxonomy, with what each acronym means structurally, what work it implies, and how to spot when someone is using the term wrong.
The work of structuring content so that AI-powered answer engines lift it as the answer to a specific question.
Where it applies: ChatGPT, Perplexity, Google AI Overviews, voice assistants, anything that produces an answer instead of a list of links.
What the work looks like: answer-first writing in the first 60 to 200 words of every page, FAQPage schema on commercial and definitional pages, named-source citations every 150 to 200 words, restructuring H2 headings as questions.
The key marker: AEO assumes the user gets a generated answer back. The optimization target is being the source of that answer.
The umbrella term covering all optimization for AI-powered generative search engines. AEO is technically a subset of GEO.
Where it applies: same engines as AEO, plus brand mentions, recommendations, and any AI-generated text where you want to appear.
What the work looks like: everything in AEO plus entity binding (Wikidata, sameAs, Knowledge Graph presence), schema beyond FAQPage (Organization, Service, Article, HowTo, DefinedTerm), and the strategic decisions about which AI engines to prioritize.
The key marker: GEO is broader than AEO. If a vendor says they do “GEO and AEO” as if they are different deliverables, the second one is a subset of the first.
A less-used term sometimes treated as a synonym for GEO, sometimes treated as a broader category covering all marketing optimization for AI surfaces (including paid AI search products, AI shopping integrations, and AI-generated product recommendations).
Where it applies: depends on who is using it. There is no settled definition. Some agencies use AIO to mean “we do everything AI-related,” which is usually not true.
What the work looks like: if someone uses AIO as a service, ask them to define it. If they cannot, the term is a marketing layer not a discipline.
The key marker: AIO is the most poorly-defined of the five. Treat any vendor leading with AIO as needing the most scrutiny on what they actually do.
The narrowest of the five. The work of structuring content specifically for LLMs (the underlying language models like GPT-5, Claude, Gemini, Llama) to surface or cite the content.
Where it applies: this is the technical layer that AEO and GEO sit on top of. LLMO would include things like training data inclusion strategies, structured data formatting for embedding extraction, and tactical writing patterns that improve LLM retrieval scoring.
What the work looks like: in practice, LLMO is mostly indistinguishable from AEO at the implementation layer. The distinction is theoretical.
The key marker: if a vendor uses LLMO without GEO or AEO, they are usually trying to sound more technical than they are. LLMO as a standalone discipline is not yet a coherent market category.
A term that exists but is not widely adopted. Functionally a synonym for GEO. Some sources treat GSO as the older or alternate name; others treat it as a Google-specific subset.
Where it applies: when used at all, GSO usually refers to the same work as GEO.
What the work looks like: identical to GEO. The only reason to use GSO over GEO is brand differentiation by a particular vendor.
The key marker: if you encounter GSO in 2026, treat it as GEO. The two terms are interchangeable in practice.
The semantically clean version, for reference:
If someone uses three or more of these acronyms in a pitch without distinguishing them, they are using vocabulary to sound informed. That does not mean their work is bad, but it means the marketing layer is doing more work than the discipline layer.
Three questions that filter the vocabulary from the work:
One: “Walk me through the difference between AEO and GEO. Do not say they are the same.”
If the vendor says “they are basically the same thing,” they are wrong. AEO is a subset of GEO that focuses on answer-format outputs. The difference is real, even if the work overlaps.
Two: “If you do GEO, what specifically do you ship for entity binding that you would not ship for AEO?”
The honest answer mentions Wikidata, sameAs arrays in Organization schema, Google Business Profile, Knowledge Graph propagation. AEO does not require entity work; GEO does. A vendor who cannot name the entity work is selling AEO and calling it GEO.
Three: “Do you use LLMO as a service line, and if so, what work is in LLMO that is not in AEO?”
The honest answer is “no, LLMO and AEO collapse to the same implementation work in 2026.” A vendor who insists LLMO is a separate discipline with separate deliverables is using vocabulary to inflate the offer.
The reason to know the taxonomy is not pedantic. It is so you can read a vendor pitch and tell whether the vendor is doing the work or just borrowing the vocabulary.
Vendors who do the work tend to use one term consistently (usually GEO or AEO, sometimes both with a clear hierarchy between them). They do not bounce between five acronyms in a single deck.
Vendors who do not do the work tend to bounce between acronyms because they are matching whatever search term brought the prospect to the call. If the prospect mentioned AEO, they pitch AEO. If the prospect mentioned LLMO, they pitch LLMO. The deck is the same, only the labels change.
The taxonomy is a tell. Use it.
For clarity on what we do: NetPageTwo uses GEO as the primary umbrella term, AEO as the subset for answer-format work, and treats AIO, LLMO, and GSO as marketing labels rather than discipline names. When buyers arrive looking for any of the five, we meet them at the term they used, then clarify the relationship if they want it clarified.
The work underneath is the same regardless of which label brought them: schema, entity binding, answer-first writing, named-source density, citation tracking, monthly iteration.
If you have heard one of these terms in a vendor pitch in the last 30 days and you were not sure what it meant, ask the vendor to explain it without using the others. If they cannot, the vocabulary is the product, not the work.
If you want an audit that distinguishes the implementation work from the marketing labels, book the fit call. We bring the page-level findings to the call.
Related reading:
– GEO 101: Generative Engine Optimization Explained
– What is Answer Engine Optimization (AEO)?
– What GEO is and what it isn’t
– NetPageTwo vs a traditional SEO agency
