Glossary

Glossary: the terms behind AI and visibility

Short, verifiable definitions of the terms that recur in our articles and on client sites: GEO, llms.txt, RAG, AI agents and more. The answer comes first, the context follows.

GEO (Generative Engine Optimization)

Visibility in AI answers, not only in search results

GEO (Generative Engine Optimization) is the set of measures that prepares a website’s content so that language models and AI search engines find it, understand it and cite it in their answers.

llms.txt

The curated entry file for language models

llms.txt is a Markdown file at the root of a website that tells language models, in a curated way, who the operator is, what it offers and which pages carry its most important statements.

LLM (Large Language Model)

The language model behind ChatGPT, Claude and Gemini

An LLM (Large Language Model) is a neural network trained on very large text corpora that can understand, generate and reason over text. Examples are GPT, Claude and Gemini.

RAG (Retrieval-Augmented Generation)

AI answers from your own documents instead of memory

RAG (Retrieval-Augmented Generation) is a method in which a language model first retrieves matching documents before answering and grounds its answer on those passages, rather than on its trained memory alone.

AI agent

An AI system that executes multiple steps autonomously

An AI agent is a system that connects a language model to tools and thereby executes multi-step tasks autonomously: it reads requests, retrieves data, decides and acts, instead of only producing text.

Structured data (Schema.org)

The grammar that search engines and AI answers build on

Structured data is machine-readable markup in a page’s HTML, usually JSON-LD following the schema.org vocabulary, that states explicitly what a piece of content is: an article, a product, an organisation, an FAQ.

E-E-A-T

Google’s yardstick for trustworthiness: experience, expertise, authority, trust

E-E-A-T stands for Experience, Expertise, Authoritativeness and Trustworthiness, the criteria by which Google, and increasingly AI systems, judge whether a source is worth citing.

Zero-click search

The answer arrives, the click never happens

Zero-click search denotes queries in which the user receives the answer directly on the results page or in the AI answer, without visiting a website.