A keygen, short for key generator, is a type of software that generates a product key or serial number for a specific software application. In the context of AutoCAD 2019, a keygen would supposedly generate a valid product key to activate the software.

The "Xforce Keygen" is a specific type of keygen that claims to generate product keys for Autodesk software, including AutoCAD 2019. However, it's essential to note that using a keygen to activate software without purchasing a legitimate license is against the terms of service and can be considered piracy.