The vocabulary is young and vendors use words loosely. Here is how we use each term, and where we think other people stretch it.
AlgoLink research team ·
How to read this page
Definitions marked as ours are working choices, not standards. No standards body governs these words, and the same term can mean two things in two vendor decks.
The terms, in plain words
AEO, answer engine optimisation
Work aimed at being the passage an answer box or assistant quotes. Older than ChatGPT: featured snippets and voice assistants used it first.
GEO, generative engine optimisation
Work aimed at being named or cited inside a model-written response. A 2023 research paper popularised the label, and marketers took it from there.
Citation
A link or footnote an answer attaches to a claim. The reader can click it, which makes it measurable.
Mention
Your brand named in the answer text with no link. Harder to track, and plausibly still useful.
AI Overview
The generated summary at the top of some Google results, launched in the US in May 2024.
AI Mode
A separate conversational Google results experience, announced in March 2025.
Grounding
Giving a model retrieved documents so its answer rests on them instead of memory. Citations usually come from this step.
Query fan-out
One question turned into many sub-searches before the answer is written. Google described it for AI Mode.
Pairs people mix up
Pair
Difference we use
Citation vs mention
A citation has a link; a mention is only text
AEO vs GEO
AEO aims at the quoted answer, GEO at inclusion in a generated one
AI Overview vs AI Mode
One sits on top of results, the other replaces them with a chat
Training data vs retrieval
Training is memory from before a cutoff; retrieval fetches live pages
Referring domain vs backlink
Distinct sites linking to you, against the total count of links
Words to be wary of
Some labels sell more than they describe. Be careful with any term attached to a score, a guarantee or a proprietary index of AI visibility.
Here is a test. A vendor that reports your share of voice in ChatGPT has to sample prompts, and the sample decides the number. Ask which prompts, which country, how often and on which dates. Honest vendors answer. Vague ones sell a dashboard.
A tidy habit helps here. Whenever a new acronym lands in your inbox, find the plainest older word it replaces. Often that is snippet, mention, citation or ranking. Our timeline of launches shows which products arrived when, and the myth table tests the loudest claims.
Two more cautions. Words invented this year may vanish next year, and the field already has rival acronyms for the same idea. Do not rebuild your strategy around a label.
Terms people ask about
Is GEO just SEO renamed?
Mostly overlapping. Pages still need to be crawlable, clear and trusted, and Google says its AI features follow normal search guidance. GEO adds attention to how passages are phrased and where else you are mentioned. Anyone claiming a separate rulebook has not shown it.
What does llms.txt do?
It is a proposal from September 2024 for a file that points models to clean versions of your pages. We have seen no major vendor confirm they use it. Adding one costs little, but do not expect a visible change.
What is a backlink in AI search terms?
The same thing as always: a link from one site to another. Whether a model weighs it is unknown. Link data still describes a site's footprint on the web, which is why we compare it across cited domains.