What is a neural network?

A neural network is a type of computer program, loosely inspired by the brain, made of many connected layers of simple units. Each connection has a strength, called a weight. During training, the weights are adjusted again and again until the network gives useful outputs. Almost all modern AI, including ChatGPT, is built on neural networks.

Why it matters for a business

Almost every modern AI model is a neural network, so the term on its own says little about a product. A network’s knowledge is spread across billions of weights rather than stored as records, which is why a model cannot look up a fact or reliably say where an answer came from. And the weights are the model: publishing that file is what makes a model open-weight.

Go deeper

How AI learns: the 4 stages of training a model

Related terms

• Deep learning
• Machine learning
• AI model
• Open-weight model
• Explainable AI

All terms, A to Z