Learner's definition of DRIVER
a person who drives a car, truck, etc.
see also backseat driver
Who was the driver at the time of the accident?
He's a good/careful/fast/bad driver.
The front door on the driver's side [=the side of the car where the driver sits] is scratched.
a person whose job is to drive a vehicle (such as a taxi, truck, or bus)
We told the taxi driver to take us to the library.
He likes to sit at the front of the bus, near the driver.
an ambulance/truck driver
a piece of computer software that controls a device (such as a mouse or printer) that is attached to the computer
a club that is used for hitting long shots off a tee
in the driver's seat
in a position in which you are able to control what happens