License

When you use something someone else made, you have to follow the terms set by its maker. The agreement that states those terms is a license. It covers things like whether you may sell it for money, whether you may change it and share it again, and whether you must credit the creator.

Open-source software and open AI models have licenses too. Some can be used freely in a business, while others allow research use only or make large companies ask for separate permission. A "right to use" that a company buys by paying for each user is also called a license.

It is like the lending rules on a library book. You can read it, but you cannot copy it and sell it. What you may and may not do is written down.

Even a "public model" may not be allowed in a business. When you hear news of a new model or dataset, looking at its license tells you who can use it and how far.