A large language model, or LLM, is an artificial intelligence system trained on an enormous amount of text. Its core trick is simple, predict the most likely next piece of text, but at scale that turns into the ability to write, summarize, translate, pull out information, and carry on a conversation.
LLMs power the AI assistants you have probably used, including ChatGPT, Claude, and Gemini. They shine at anything that involves language and structure, which makes them useful for drafting, summarizing, and answering questions.
Their catch is that they generate plausible text rather than retrieve verified facts, so they can hand you a confident, well-written, wrong answer. People call that a hallucination. For business use, the reliable pattern is to keep a person in the loop and ground the model in your own trusted data with retrieval-augmented generation.
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