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.
Pe"dal (?), n. [Cf. F. pÈdale, It. pedale. See Pedal, a.] 1. (Mech.) 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.