In their own words.
Our plain version above is ours. This is the official or expert wording we based it on.
“the class of AI models that emulate the structure and characteristics of input data”
Related words.
Large language model (LLM)
An AI model trained on huge amounts of text to predict the next piece of text, which lets it answer questions, write and summarize. ChatGPT, Claude and Gemini are built on LLMs.
Foundation model
A large general-purpose model trained on a broad mix of data, which other products and more specialized models are then built on.
Artificial intelligence (AI)
Computer systems that do things we would normally say need human intelligence, such as understanding language, recognizing images, making predictions or making decisions.
Model
The trained program at the heart of an AI product: a large set of learned numbers that turns an input (your question) into an output (its answer). ChatGPT is a product; GPT-5 is a model.
Neural network
The kind of model behind modern AI: layers of simple maths units, loosely inspired by brain cells, connected by adjustable weights.
Machine learning
The part of AI in which computers learn patterns from examples and data instead of being given step-by-step rules.