AEO, GEO, AI SEO: the 2026 glossary

Why the terminology is a mess

In two years the field went from one term (SEO) to half a dozen, coined by different people for overlapping problems. The acronyms got out before the practices stabilised, so most blog posts treat them as synonyms when they aren't, or treat them as opposites when they aren't. The result is a lot of decks selling “you need GEO not SEO” — which is wrong in both directions. Here is the version that holds up.

The terms, in plain language

SEO — Search Engine Optimization

The original discipline. Getting your pages to rank well on classic search engines (Google, Bing, DuckDuckGo) for queries that produce a list of blue links. SEO is alive and well in 2026 — most users still start with Google for transactional and navigational queries — but it's no longer the whole game. It's the foundation everything else builds on, because the crawlability, structure and content quality that win at SEO are roughly the same that win at AEO and GEO.

AEO — Answer Engine Optimization

The umbrella term for being the answer in any answer-shaped surface, regardless of how it was generated. That includes Google featured snippets, People Also Ask, Alexa/Siri/Google Assistant voice answers, Bing chat cards, and yes — LLM chats. AEO predates the LLM boom; the term was coined for voice and snippets around 2015 and got new life when chat assistants started behaving like answer engines. If you're optimising for “the one box at the top,” you're doing AEO.

GEO — Generative Engine Optimization

The newer term, scoped specifically to LLM-generated answers — ChatGPT, Claude, Gemini, Perplexity, Copilot, Doubao, Grok. Coined in a 2023 academic paper that tried to quantify what content traits caused models to cite a source; the term then escaped into marketing. GEO is a strict subset of AEO: every generative engine is an answer engine, but not every answer engine is generative (Siri's 2019 weather reply was AEO, not GEO). When someone says “GEO,” they almost always mean “optimising for being cited inside an LLM reply.”

LLMO / AI SEO

LLMO (LLM Optimization) and AI SEO are loose synonyms for GEO, used interchangeably in most blog posts and most LinkedIn decks. There's no meaningful technical distinction. Pick the term your audience already uses. We default to “AI visibility” on this site because it's the term non-specialists actually Google.

What stays the same from classic SEO

About 70% of the work. Crawlable HTML, fast pages, sensible information architecture, descriptive titles, single H1 per page, clean internal linking, real schema.org markup, a usable sitemap.xml, no broken canonicals. If you've done good SEO for five years, you are most of the way to good AEO and GEO already. Anyone selling you a “GEO rewrite” that ignores your existing technical SEO foundation is selling you nothing.

What is actually new

The genuinely new 30% breaks into three layers:

• Per-bot crawlability. Googlebot is no longer the only crawler that matters — GPTBot, ClaudeBot, PerplexityBot and Google-Extended each fetch independently, and your CDN may block some without you noticing. See robots.txt for AI crawlers.
• Structured legibility for extraction. Classic SEO rewards good structure; AEO and GEO require it. Models cite sentences they can attribute, which means clean JSON-LD, predictable headings, answer-first copy, and citable snippets — see the schema.org guide.
• Entity authority. LLMs disambiguate based on whether the entity (your brand, your authors) exists clearly in their training and retrieval — Wikipedia, LinkedIn, GitHub, Crunchbase, a strong sameAs graph. Classic SEO cares about backlinks; GEO cares about entity coherence across the open web.

There is also a fourth, harder-to-measure layer: llms.txt as an editorial signal, covered in our llms.txt deep dive. Adoption is still early but the cost is near zero.

Which term to use when

Pragmatic guidance: in conversations with a CMO or marketing director, use “AI visibility” or “AI SEO” — they map cleanly to existing mental models. In a technical RFC or a vendor brief, use “GEO” (precise) or “AEO” (broader, includes voice and snippets) — they avoid implying classic SEO is dead. In public marketing copy, use whichever your target customer is already searching for; a quick Google Trends check beats any opinion. Whatever term you pick, the work is the same: be reachable, be legible, be specific, be measurable.

FAQ

Whatever you call it, measure it: run a free audit, or start with the five-step checklist for being cited by AI assistants.