Open weights
Also: open-weight
A model whose trained weights are published for anyone to download and run, as opposed to one reachable only through an API. Open weights do not by themselves guarantee an open licence or open training data.
A model has open weights when its trained parameters are published for download, so you can run it on your own hardware. This is the foundation of local AI: without the weights, a model can only be used through someone else’s API.
Open weights are not the same as fully open, though. The licence may still restrict commercial use, and the training data and code are usually not released. A model can be freely downloadable yet carry meaningful conditions, which is why the catalogue records the licence and commercial-use terms separately for each entry rather than treating “open” as a single yes or no.