LLM (Large Language Model)
A large language model (LLM) is the type of AI system like GPT, Gemini or Claude that generates the answers behind AI search.
What is an LLM?
A large language model (LLM) is an AI system trained on vast amounts of text to predict and generate language. Given a prompt, it produces a fluent, context-aware response the technology powering ChatGPT, Gemini, Claude, Perplexity and Copilot.
LLMs are the engine of AI search: when a user asks an assistant about your category, an LLM is what decides which brands to name and how to describe them.
How LLMs generate answers
An LLM responds to a prompt by predicting the most likely next words based on patterns it learned in training. On its own, that knowledge is frozen at the training cut-off.
To stay current and accurate, modern systems add grounding: retrieving live sources and folding them into the answer. That is why what an LLM says about your brand depends both on its training data and on the content it can retrieve right now.
LLMs and your brand
Each LLM forms its own picture of your category, so your AI Visibility can differ sharply from one to the next. That is why GEO has to be measured per engine, not as a single average.
The LLMs Prominence AI tracks
Prominence AI tracks how your brand appears across the major engines: ChatGPT, Gemini, Perplexity, Copilot and Google's AI Overviews and AI Modeone consistent view of your visibility across all of them.
Retrieval-Augmented Generation (RAG)
Retrieval-Augmented Generation: grounding a model’s answer in sources fetched at query time rather than memory alone.
Hallucination
An AI hallucination is when a model states something false with complete confidence, presenting invented or incorrect information as if it were fact.
Knowledge Graph
A knowledge graph is a structured map of entities, things like companies, people, products, and places, and the relationships between them.
Grounding
The process by which an AI model bases its answer on external sources or live web results rather than only its training data.
Prompt
The natural-language input a user gives an AI model to get an answer, and the core unit of measurement in AI Search and GEO.
Written by
Andreas Niessen
Co-Founder, Prominence AI
Andreas Niessen is Co-Founder of Prominence AI, the brand rank tracker for AI search engines. He works daily with how ChatGPT, Gemini, Perplexity and Copilot describe brands, and writes about Generative Engine Optimization (GEO), AI Search and brand visibility in the AI era.
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