Pedal /(pē"dal in def 1; 277)/

Pe·dal

Pedal

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

Pedal curve: 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: the note which is held or sustained through an organ point. See Organ point, under Organ.
Pedal organ: 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.

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. (Mech.)
A pedal curve or surface. (Geom.)