Pedal

Part of speech: noun (n.)

1. A lever or key acted on by the foot, as in the pianoforte to raise the dampers, or in the organ to open and close certain pipes; a treadle, as in a lathe or a bicycle.

2. A pedal curve or surface.

Part of speech: adjective (a.)

1. Of or pertaining to the foot, or to feet, literally or figuratively; specifically (Zoöl.), pertaining to the foot of a mollusk; as, the pedal ganglion.

2. Of or pertaining to a pedal; having pedals. Pedal curve or surface (Geom.), the curve or surface which is the locus of the feet of perpendiculars let fall from a fixed point upon the straight lines tangent to a given curve, or upon the planes tangent to a given surface. -- Pedal note (Mus.), the note which is held or sustained through an organ point. See Organ point, under Organ. -- Pedal organ (Mus.), an organ which has pedals or a range of keys moved by the feet; that portion of a full organ which is played with the feet.