pedal curve

Pedal \Pe"dal\ (p[=e]"dal in def 1; 277), a. [L. pedalis, fr.
   pes, pedis, foot. See {Foot}, and cf. {Pew}.]
   1. 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.
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   2. (p[e^]d"al) Of or pertaining to a pedal; having pedals.
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   {Pedal curve} or {Pedal 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.
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