LLM (Large Language Model)
An LLM is the kind of AI that reads questions and writes answers — the engine inside ChatGPT, Gemini, Claude, and the AI summaries you now see on Google.
What it is
An LLM — short for large language model — is a piece of software trained on enormous amounts of text from the internet, books, and other sources. After all that training, it learns to predict what words should come next, which is why it can answer questions, summarize articles, write emails, and have a back-and-forth conversation.
The popular consumer LLMs are ChatGPT (OpenAI), Gemini (Google), Claude (Anthropic), Grok (xAI), and Perplexity (which combines an LLM with live web search). Microsoft's Copilot and Meta AI sit on top of LLMs too. The same model is also what powers Google's AI Overviews at the top of search results.
Why it matters for your business
Customers are increasingly asking LLMs the kind of questions they used to type into Google — "what's a fair price for X?", "who's a good plumber in Y?", "is Z company reliable?" — and treating the answer as if it came from a knowledgeable friend. If the LLM doesn't know your business, you're invisible to that user. If it knows your business but gets the facts wrong (wrong hours, wrong service area, outdated services), it may quietly steer the customer to a competitor.
Example
Someone moving to Denver opens ChatGPT and types "best HVAC repair company in north Denver." The LLM has read your company's website, your Google Business Profile, and several local reviews — and because all three say the same things in the same way (consistent address, same services, same hours), it confidently recommends you over a competitor whose information is contradictory. You get a call you'd never have gotten from a Google ad.
Related
- Guide: Traditional SEO vs AI SEO (AEO/GEO), AI Discovery Surfaces (AEO/GEO playbook)
- Related terms: AEO, GEO, AI Overviews