The Legend Capture Card - Crossbar Windows Driver refers to a driver software that enables communication between the Legend Capture Card (which is a hardware device used for video capture) and the Windows operating system. The "Crossbar" term refers to the software interface or control mechanism that manages video input and output streams between the capture card and other devices, such as cameras, TVs, or recording equipment.

In simple terms, the driver allows the operating system to recognize the capture card and use its features, such as video input/output, resolution settings, and other functionalities related to video capturing, streaming, or editing.