Pedal (noun)

1. A lever or bar that is pushed down with the foot to operate a machine or vehicle.
2. A lever or bar that is pushed down with the foot to provide power or motion.
3. A lever or bar that is pushed down with the foot to produce sound or control the volume on a musical instrument such as a piano or organ.

Origin:

From the latin pedale "foot-stool", from pes "foot".

Examples:

1. He pressed the pedal to accelerate the car.
2. She pressed the pedal to make the sewing machine go faster.
3. The pedal on the bike was loose and needed tightening.
4. He used the pedal to make the organ louder.
5. She used the pedal to make the piano softer.