Large language model (LLM)
What is Large language model (LLM)?
A model trained on huge amounts of text to understand and generate language. It works by predicting the next word over and over, from patterns it picked up in training. Chatbots, copilots and most generative AI tools run on one. The "large" refers to the number of internal parameters, now often in the hundreds of billions.
Why it matters
An LLM is the engine under most of the AI tools a business actually touches: the assistant in the helpdesk, the copilot in the code editor, the chatbot on the website. Because one general model can draft text, answer questions, translate and summarize, companies no longer buy a separate narrow tool for each of those jobs. That is the shift. The same model handles many tasks, and you steer it with instructions rather than retraining it. The flip side is cost and control. A model this large runs on serious hardware, and it will occasionally state something wrong in fluent, believable prose.
In practice
A bank points an LLM at its product FAQs so customers get answers in plain language at 2am. A law firm uses one to summarize 100-page contracts down to the clauses that matter. A retailer drafts thousands of product descriptions from a spec sheet. None of these needed a bespoke model. They needed a general one, pointed at the right data with clear instructions.
