Being behind the wheel is a phrase used to describe someone who is driving a vehicle. It is often used to refer to the driver of a car, but can also be used to refer to the pilot of an aircraft or the captain of a boat. The term 'STEER' is a five-letter word that is used to describe the act of controlling the direction of a vehicle. Steering is done by turning the wheel in the desired direction, which is why the phrase 'behind the wheel' is used to refer to the person driving the vehicle.