---
title: "What Is a Large Language Model (LLM)? Definition | ONEGTMLAB"
description: "A large language model (LLM) is an AI model trained on large amounts of text to understand and generate language. Learn how LLMs are used in GTM."
canonical: https://www.onegtmlab.dev/glossary/large-language-model
---

# What Is a Large Language Model (LLM)? Definition | ONEGTMLAB

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GTM Glossary

# Large Language Model (LLM)

A large language model (LLM) is a type of AI model trained on very large amounts of text to predict and generate language, which lets it answer questions, summarize, write and follow instructions.

Also called: LLM

## Why it matters

LLMs are the engine behind AI assistants, AI search features and AI agents. In go-to-market work they draft and personalize messages, summarize calls and accounts, classify replies and leads, research companies and turn unstructured text, such as job posts or websites, into structured data teams can act on.

LLMs generate likely text rather than look up facts, so they can state wrong information confidently, often called hallucination. Teams get reliable results by giving the model the right context, asking for structured output, grounding answers in real source data and checking important outputs. Prompt engineering and context engineering are the practices for doing this well.

## Example

A sales team gives an LLM a company's website text and a short description of its ideal customer, then asks it to return whether the company fits, a one-sentence reason and a confidence level. A person reviews a sample of the answers before the team uses the results to choose which accounts to contact.

## Related terms

-   [Prompt Engineering](/glossary/prompt-engineering)
-   [Context Engineering](/glossary/context-engineering)
-   [AI Agent](/glossary/ai-agent)
-   [Generative Engine Optimization (GEO)](/glossary/generative-engine-optimization)
-   [llms.txt](/glossary/llms-txt)

## Related service

[GTM Engineering Signal-led outbound systems that enrich, score, sequence and sync to your CRM.](/ai-gtm-engineering)

## Related playbooks

-   [Claude Code for Sales Run list builds, qualification, outreach and CRM sync from one terminal, with every judgment written down.](/growth-playbooks/claude-code-for-sales)
-   [Claude Code for Marketing Content, SEO, page research, link building and lead magnets, run as repeatable skills instead of one-off prompts.](/growth-playbooks/claude-code-for-marketing)

[← All GTM terms, A to Z](/glossary)

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