The Collaborative International Dictionary of English v.0.48:

Pedal \Pe"dal\ (p[e^]d"al), n. [Cf. F. p['e]dale, 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.
      [1913 Webster]

   2. (Geom.) A pedal curve or surface.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

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.
      [1913 Webster]

   2. (p[e^]d"al) Of or pertaining to a pedal; having pedals.
      [1913 Webster]

   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.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pedal
    adj 1: of or relating to the feet; "the word for a pedal
           extremity is `foot'"
    n 1: a sustained bass note [syn: pedal point, pedal]
    2: a lever that is operated with the foot [syn: pedal,
       treadle, foot pedal, foot lever]
    v 1: ride a bicycle [syn: bicycle, cycle, bike, pedal,
         wheel]
    2: operate the pedals on a keyboard instrument

Moby Thesaurus II by Grady Ward, 1.0:

82 Moby Thesaurus words for "pedal":
   advance, bar, beam, bicycle, bike, boom, bowl, bunt, bus, butt,
   cant hook, catch a train, chauffeur, choir, claviature, claw bar,
   clawed, console, crank, crow, crowbar, cycle, drive, echo,
   eighty-eight, entrain, fingerboard, footed, forward, go by rail,
   great, handspike, hoofed, impel, iron crow, ivories, jimmy,
   joyride, keyboard, keys, lever, limb, make a train, manual,
   marlinespike, motor, motorcycle, move, organ manual, outrigger,
   peavey, pedals, piano keys, pinch bar, plantar, pole, prize,
   propel, pry, push, ride, ripping bar, roll, row, shove, shunt,
   solo, spar, sweep, sweep along, swell, take a joyride, taloned,
   taxi, thrust, toed, treadle, troll, trundle, ungulate, wheel,
   wrecking bar