Model

AI model

In one sentenceThe trained "brain" inside an AI product. ChatGPT is an app; GPT is the model running inside it.

What it means

A model is the result of training: a big file of learned patterns that turns your input into an output. Apps like ChatGPT, Claude and Gemini are the interface; the model is the engine underneath.

Companies release new model versions often, and a single app may offer several: a fast, cheaper one for quick tasks and a slower, smarter one for hard problems.

How to use it

• When a tool lets you pick a model, use the fast one for quick rewrites and the most capable one for strategy, research and anything high stakes.
• If results suddenly change in a tool you use every day, the model may have been upgraded. Re-test your favorite prompts.

Related terms

LLM Harness Foundation Model Reasoning Model Open-Weight Model