Glossary
Model Licence
Short answer
The legal text defining how an AI model may be used.
For open-weight models, the licence determines whether commercial use is possible, and it changes from version to version.
The most common trap is different versions of the same model family shipping under different licences. In Flux, Schnell is cleared for commercial use and Dev is not; most users do not know the difference.
If you use a model through a platform, it is common for the platform not to state which version it runs. Ask before commercial work.