Pedal

• gas pedal: a lever in an automobile that, when depressed, gives more fuel to the automobile's engine.
• bicycle pedal: a lever on a bicycle that, in combination with the crank arms, turns the gears.
• organ pedal: a pedal on an organ that acts like a key on the organ keyboard; when depressed, it causes a note (or group of notes) to sound.

Geometry: see also pedal triangle, pedal curve[?].