Pedal \Pe"dal\, 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 (Zo["o]l.), 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.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Pedal \Pe"dal\, 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.

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

Source: Webster's Revised Unabridged Dictionary (1913)