What is an LLM?
An LLM (large language model) is the text engine inside tools like ChatGPT, Claude, Gemini, and Grok. It predicts a useful next sentence from the text you gave it and the text it was trained on.
Also called: large language model, foundation model
In plain English
It is not a database of your shop. It is a very fluent writer that has read a lot. It can draft, summarize, and rewrite. It can also invent a fact that sounds normal. Your ledger, your calendar, and your SOP are the records. The model is the pen. You are renting a general writer, not hiring a bookkeeper who already knows your tax year. The useful test is boring: paste one real job, hide the answer, and see if the draft matches what a trained employee would send. If it needs your files every time, that is normal. The model is the pen. The files are the memory. Judge it on a job you already know how to do, with the answer covered.
How an owner would use it
Use an LLM to turn a brain dump into a draft. Paste the facts it is allowed to use. Read the draft out loud before it goes to a customer or an applicant.
Common mistakes
An LLM is a writer, not a witness. Owners paste a question with no facts and treat the fluent answer as a lookup. That is how invented prices and fake policies get into a quote. Do not use the model as the place a number lives. Do not fine-tune or 'train' it because a draft was generic. Give it the row from your sheet.
A worked example
A neighborhood retailer
A Saturday recap
This is an illustration, not a customer result. The owner exports Saturday's real totals, pastes them in, and asks for a five-line note to the weekend crew. The model writes the note. It does not get to decide what Saturday's sales were.
Related terms
Prompts and guides
Questions owners ask
What is an LLM?
A large language model is the writing engine inside an AI chat app. It drafts from your prompt and from what it learned in training. It is not your system of record.
How do I use an LLM as an owner?
Give it the facts, ask for a draft, and check the draft. Good first jobs are reminder emails, job posts, and SOP outlines.
Is an LLM the same as ChatGPT?
ChatGPT is a product that uses large language models. Claude, Gemini, and Grok are other products on the same idea. The product adds accounts, files, and tools. The model is the writing engine inside.
Product guides are on AI apps for business.