What does device driver mean?
A device driver is operating-system software that helps the system control and exchange information with a hardware device. Its job is to connect general system requests to the device's supported behavior. The word 'driver' describes a role, not necessarily a separate program the user opens.
A driver may come with the operating system, arrive through its update service, or be supplied by a hardware or computer maker. One task can involve multiple drivers, and one downloaded installer can contain other software too. Whether a replacement is appropriate depends on the exact hardware, supported system version, and the problem or feature being addressed.
Example in context
When a document is printed, the application requests output, Windows manages a queue, and printer support software helps produce commands the selected printer understands. If the printer has no paper, the driver is still present; changing it cannot supply paper. If the wrong model's driver is selected, however, available paper sizes or output may be wrong.
A common misunderstanding
A frequent mistake is treating 'device has a driver' as 'device works perfectly.' Detection and a loaded driver do not prove that a cable, speaker, printer mechanism, or network link works. Similarly, an older driver version does not automatically mean a device needs updating. Observe the failing task before attributing it to software.
How to use this term
When a problem appears, specify the operation and connection first: 'the USB printer is detected but cannot print through this queue' is more useful than 'the driver is broken.' If the device works on another computer, the comparison narrows the investigation but does not conclusively prove a software cause. A driver is one layer in a working chain that also includes power, connections, settings, and the hardware itself. Treat it as a candidate to verify, not the automatic answer.
Compare [operating system](/glossary/operating-system), [firmware](/glossary/firmware), and [driver package](/glossary/driver-package) for the surrounding layers. If you need to inspect the installed version, use [identify device and driver version](/how-to-update-device-drivers/identify-device-and-driver-version); for a conceptual introduction read [what is a device driver](/blog/what-is-a-device-driver).