Open Weights
A type of AI release where the trained model is available to download, but the original training data and code are kept secret.
In Plain English
Open weights is a middle ground between open-source and closed-source AI. The company does the incredibly expensive work of training the AI, and then lets the public download the finished brain (the weights/parameters). Developers can run it on their own computers and build apps with it, but they cannot see exactly how it was made. It is like giving someone a baked cake, but not the recipe.
Real-World Example
A researcher downloading Meta's Llama model to their laptop to build an offline medical chatbot.