# Large language model (LLM)

Category: [AI Search & GEO](https://seo-geo-glossary.com/en/glossary/category/ai-search-geo/) › [AI & LLM basics](https://seo-geo-glossary.com/en/glossary/category/ai-search-geo/ai-llm-basics/) · Also known as: LLM, language model

A **large language model** (LLM) is an AI model trained on very large amounts of text that generates language by repeatedly predicting the most likely next piece of text. The model families behind ChatGPT, Gemini and Claude are well-known examples. In legal education, LLM (or LL.M.) also stands for Master of Laws; this entry covers the AI meaning.

## How does an LLM work?

Today's LLMs are built on the **transformer** architecture, introduced by Google researchers in the paper "Attention Is All You Need," first posted on June 12, 2017. A transformer uses self-attention to weigh, for every part of the input, which other parts of the context matter for it.

Text is split into **tokens** before processing. A token can be a whole word, part of a word or a single character. In **pretraining**, the model learns to predict tokens on large text collections. It is then usually fine-tuned with examples and human feedback so it follows instructions and gives helpful answers.

An LLM does not store a copy of the web pages it was trained on. It produces answers from statistical patterns learned in training. That explains **hallucinations**, statements that sound plausible but are wrong. Its knowledge also stops at the date of its training data, unless the application around it fetches current information.

## Why do LLMs matter for SEO?

Website content can reach an AI answer in two ways:

| Path | What happens | Example at OpenAI |
|---|---|---|
| Training | Crawlers collect content that may be used for future models | GPTBot |
| Retrieval at answer time | The system searches the web for a question and uses the pages it finds as sources | OAI-SearchBot (ChatGPT search), ChatGPT-User (user-triggered actions) |

OpenAI documents that each of these bots can be controlled separately in robots.txt. A site can block GPTBot and still appear in ChatGPT search through OAI-SearchBot. For ChatGPT-User, OpenAI notes that robots.txt rules may not apply because a user triggers the request. Anthropic uses a similar split with ClaudeBot (training), Claude-User and Claude-SearchBot.

Retrieval at answer time works much like a search engine visit. The page has to be reachable, readable without heavy client-side hurdles, and not blocked for the bot in question.

## Example

A user asks an AI assistant about the return policy of an online shop. Without web access, the model guesses from older training data. With search enabled, the assistant fetches the shop's current returns page and cites it. If that page blocks the provider's search bot, the answer has to rely on third-party sites instead.

## FAQ

**Is ChatGPT an LLM?**
ChatGPT is an application by OpenAI that runs on LLMs from the GPT series. The model generates the text, while the application adds web search, file uploads and conversation history.

**What is the difference between LLM and GPT?**
LLM is the general category. GPT (generative pre-trained transformer) is the name of OpenAI's model series within that category.

**What does LLM stand for?**
Large language model. "Large" refers to the amount of training data and the number of model parameters.

## At a glance

- **Type:** AI model for language (language model with a very high number of parameters)
- **Architecture:** [usually Transformer (Vaswani et al. 2017)](https://arxiv.org/abs/1706.03762)
- **Used in:** ChatGPT, Gemini, Claude and AI search
- **Docs:** [Google: Machine Learning Glossary, large language model](https://developers.google.com/machine-learning/glossary#large-language-model)

Last checked: October 8, 2026

## AI search: from ChatGPT to AI Mode

- **November 30, 2022:** OpenAI releases ChatGPT as a free research preview. The model is based on the GPT-3.5 series. ([Source](https://openai.com/index/chatgpt/))
- **February 6, 2023:** Google announces its conversational AI service Bard and opens it to trusted testers first. ([Source](https://blog.google/technology/ai/bard-google-ai-search-updates/))
- **February 7, 2023:** Microsoft launches the new Bing with AI chat and complete answers inside search. ([Source](https://blogs.microsoft.com/blog/2023/02/07/reinventing-search-with-a-new-ai-powered-microsoft-bing-and-edge-your-copilot-for-the-web/))
- **May 10, 2023:** Google introduces the Search Generative Experience (SGE) as an experiment in Search Labs. At launch it is limited to the US and English. ([Source](https://blog.google/products/search/generative-ai-search/))
- **November 15, 2023:** Microsoft renames Bing Chat to Copilot. General availability follows from December 1, 2023. ([Source](https://blogs.microsoft.com/blog/2023/11/15/microsoft-ignite-2023-ai-transformation-and-the-technology-driving-change/))
- **May 14, 2024:** At Google I/O, Google announces AI Overviews for everyone in the US, with more countries to follow. ([Source](https://blog.google/products/search/generative-ai-google-search-may-2024/))
- **July 24, 2024:** Bing previews its generative search experience. At first it appears for a small share of queries only. ([Source](https://blogs.bing.com/search/July-2024/generativesearch))
- **July 25, 2024:** OpenAI tests SearchGPT as a temporary prototype with a small group of users and publishers. ([Source](https://openai.com/index/searchgpt-prototype/))
- **October 28, 2024:** AI Overviews roll out in more than 100 countries and territories. Google expects more than 1 billion monthly users. ([Source](https://blog.google/products/search/ai-overviews-search-october-2024/))
- **October 31, 2024:** OpenAI launches ChatGPT search, first for paying users and the SearchGPT waitlist. Answers link to their sources. ([Source](https://openai.com/index/introducing-chatgpt-search/))
- **December 11, 2024:** Google launches Deep Research in Gemini Advanced. It browses the web on its own and compiles a report. ([Source](https://blog.google/products/gemini/google-gemini-deep-research/))
- **December 16, 2024:** ChatGPT search becomes available to all logged-in users in regions where ChatGPT is offered. ([Source](https://openai.com/index/introducing-chatgpt-search/))
- **February 2, 2025:** OpenAI introduces deep research in ChatGPT, starting with Pro users. ([Source](https://openai.com/index/introducing-deep-research/))
- **February 5, 2025:** ChatGPT search becomes available without signing up in all regions where ChatGPT is offered. ([Source](https://openai.com/index/introducing-chatgpt-search/))
- **March 5, 2025:** Google introduces AI Mode as an experiment in Search Labs. Google One AI Premium subscribers get access first. ([Source](https://blog.google/products/search/ai-mode-search/))
- **March 20, 2025:** Anthropic adds web search with citations to Claude. It launches as a preview for paid users in the US. ([Source](https://www.anthropic.com/news/web-search))
- **March 26, 2025:** AI Overviews launch in Germany in German and English, together with other European countries. They are shown to signed-in users aged 18 and over. ([Source](https://blog.google/intl/de-de/produkte/suchen-entdecken/uebersicht-mit-ki-start/))
- **May 20, 2025:** At Google I/O, Google rolls out AI Mode to everyone in the US, with no Labs sign-up needed. ([Source](https://blog.google/products/search/google-search-ai-mode-update/))
- **May 20, 2025:** AI Overviews are available in more than 200 countries and territories and in more than 40 languages. ([Source](https://blog.google/products/search/ai-overview-expansion-may-2025-update/))
- **May 27, 2025:** Web search in Claude becomes available globally on all plans. ([Source](https://www.anthropic.com/news/web-search))
- **June 16, 2025:** Data from AI Mode counts towards the totals in the Search Console Performance report. ([Source](https://developers.google.com/search/updates#ai-mode-is-now-counting-towards-totals-in-search-console))
- **October 8, 2025:** AI Mode launches in Germany, Austria and Switzerland as part of an expansion to more than 40 new countries and territories. ([Source](https://blog.google/intl/de-de/produkte/suchen-entdecken/ki-modus-startet-in-dach/))
- **June 3, 2026:** Search Console adds dedicated performance reports for generative AI features such as AI Overviews and AI Mode, first for a subset of sites. ([Source](https://developers.google.com/search/blog/2026/06/gen-ai-performance-reports))
- **August 31, 2026:** The Search Console reports on generative AI features become available to all websites worldwide. ([Source](https://developers.google.com/search/blog/2026/06/gen-ai-performance-reports))

## Not to be confused with

- [Generative AI](https://seo-geo-glossary.com/en/glossary/generative-ai/index.md): is the umbrella term for AI models that create new content such as text, images, audio or video. LLMs are the language models within it that generate text.

## Related terms

- [Token](https://seo-geo-glossary.com/en/glossary/token/index.md)
- [AI hallucination](https://seo-geo-glossary.com/en/glossary/ai-hallucination/index.md)
- [Retrieval-augmented generation (RAG)](https://seo-geo-glossary.com/en/glossary/retrieval-augmented-generation/index.md)
- [AI crawler](https://seo-geo-glossary.com/en/glossary/ai-crawler/index.md)
- [GPTBot](https://seo-geo-glossary.com/en/glossary/gptbot/index.md)
- [OAI-SearchBot](https://seo-geo-glossary.com/en/glossary/oai-searchbot/index.md)
- [AI Overviews](https://seo-geo-glossary.com/en/glossary/ai-overviews/index.md)
- [AI share of voice](https://seo-geo-glossary.com/en/glossary/ai-share-of-voice/index.md)

## Sources

- [Vaswani et al.: Attention Is All You Need, arXiv:1706.03762 (submitted 2017-06-12)](https://arxiv.org/abs/1706.03762)
- [Machine Learning Glossary: large language model – Google for Developers](https://developers.google.com/machine-learning/glossary#large-language-model)
- [Ouyang et al.: Training language models to follow instructions with human feedback, arXiv:2203.02155 (2022)](https://arxiv.org/abs/2203.02155)
- [Overview of OpenAI Crawlers – OpenAI](https://developers.openai.com/api/docs/bots)
- [Does Anthropic crawl data from the web? – Claude Help Center](https://support.claude.com/en/articles/8896518-does-anthropic-crawl-data-from-the-web-and-how-can-site-owners-block-the-crawler)
- [Large language model – Wikipedia (secondary, for training stages and terminology)](https://en.wikipedia.org/wiki/Large_language_model)

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Last updated: October 8, 2026
URL: https://seo-geo-glossary.com/en/glossary/large-language-model/