Why does the word ‘sport’ light up on my dashboard?

I have a 2013 Nissan X-trail. There is a button on the gear lever that lights up the word “Sport” on the dashboard. What does it mean and what does it do? RI 

Almost nothing physically. A little bit psychologically. Many recent models have the “Sport” option, and most of them only change the sensitivity of the accelerator pedal.

On all cars, acceleration is achieved by opening a tap which allows petrol into the engine. The more you open the tap, the more petrol arrives, the more power is generated and the car accelerates.

The tap (in the carburettor or injector) is called the “throttle”, and is opened or closed by the driver via a wire cable attached to the accelerator pedal. If you pressed the accelerator half way down, the throttle half opens. 

Nowadays a system called ETC (Electronic Throttle Control) is increasingly common. Instead of using a wire cable, the accelerator pedal operates a little electric motor which adjusts the throttle opening (like turning up the volume knob on a radio).

In normal mode, a half-pressed accelerator pedal will half open the throttle. But in “Sport” mode the electric motor setting is changed, so the throttle initially opens by more than the pressure on the accelerator. It makes the car feel brighter and more responsive but does nothing that cannot be achieved by pressing the accelerator harder. Actual “performance” is unchanged.

On more high performance cars, which often have highly sophisticated computerised management of many functions, the “Sport” setting not only changes the ETC but also the stiffness of the suspension, the turning ratio of the steering, and tells the automatic gearbox to allow higher revs before changing gear, and can even alter things such as computerised traction control and gear ratio steps. Those can make a real difference to how a car handles and performs. ETC on its own does not. The maximum size of the “tap” does not change, whether it is opened by a wire cable or an electric motor.